Totally fine

What are you doing here?

Izuku woke up by a loud sneeze. He opened his eyes after another, little one. His head was pounding when he coughed for a moment. He still had an hour before his alarm clock will wake him up for training.
'Great, I have an hour to review my notes before school today' was the first thought that came to his mind. 'I'll just go wash my face to calm my little head ache, and then study a bit before morning work out'. He knew better than to combine pain killers and an intense work out.
Slowly, Izuku got out of bed and walked to the common washroom. He had some assistance from the corridor wall, since he was a little dizzy. 'Sleepy' he thought.

After washing his face and brushing his teeth, he walked back slowly (thank you wall) to his room, changed from his sleeping pants to his work out pants, and added a hoodie for his study session. He was shivering, still.
As he reviewed his notes, his coughes became louder, and the sneezes more frequent. He tried muffling those with a tissue. 'Don't want to bother the other guys' he thought, leaning his heavy, throbbing head on his desk for a moment.
He realized he was sleeping when the alarm clock from his night stand woke him. He stood up quickly in order to silence the ringing before it interrupts anyone else, and his vision was filled with black spots. He felt light headed, collapsing to the floor with a loud thud, loosing consciousness on the way down.

A knock on the door. Mineta was calling for Izuku to silence that damned ringing, it woke him from a wonderful dream about Uraraka using her quirk on Yaomomo's costume by accident during training. When no one is answering, Mineta opens the door to see a shivering Midoriya laying on the floor near his desk. "Whoa!" he shouts, as Tokoyami comes with Aoyama.
Tokoyami, as cool headed as ever, uses Dark Shadow to stop the alarm while he's pressing a palm to Izuku's forehead. "He has a fever" he determines, looking at the other two boys. He then uses Dark Shadow to lift the limp Midoriya off the floor and into his bed.
The moment his head touches the pillow, Izuku's eyes flash open and he sits up immediately. Aoyama gets closer to convince him to lay down, but Izuku doesn't even notice there are other people in his room. He stands up, one hand pressed to his mouth and the other hugs his abdomen, and dash to the common washroom. The three teens follow him with concerned looks on their faces.

After a session of sick Midoriya being sick towards the toilet, Tokoyami comes to him with a glass of water in his hand. Izuku looks at him, terrified. He didn't know someone else was there. "I'm fine" he mumbles weakly, refusing the gesture. He winces and turns back to the toilet, begging Tokoyami to step back from him. More retching sounds are heard, Midoriya loosing the fight against his stomach.
When he finishes emptying his stomach and depleting his will-to-live reserves, Izuku moves to lean his back against the stall's wall. His face is pale and sweaty, his body shivering from both fever and exhaustion. Tokoyami hands him the glass of water which Midoriya now accepts, taking small sips. "Are you ready to go back to bed?" Asks the bird headed boy, waiting for the greenette's response. A small nod followed by his struggle to lift himself off the floor send Tokoyami to his aid, giving him a hand and finally- letting Dark Shadow lift him and carry him back to bed.
"Aoyama, please go and call Aizawa sensei. Tell him Midoriya is sick. Then please go to the kitchen and bring a bowl of icy water and a washcloth. Mineta, you go to the washroom again and bring a thermometer and fever reducers from the first aid cabinet. I'll be here watching him for now" said Tokoyami, and the others nodded and went to fulfill their tasks. Tokoyami sat on the chair and looked at the pale boy's face, his black bags under his eyes and the little freckles more prominent against the white, damp skin.

Mineta was the first to come back, carrying a special ear-thermometer and a package of pills. He took Midoriya's temperature: 39.2 c. Izuku coughed some more, wincing at the strain on his sore throat.
Aoyama came next, holding a full bowl and the wash cloth on his forearm. Tokoyami prepared the wet cloth and pressed it to the sick boy's forehead. Izuku's eyes were half lidded as he looked at Tokoyami's eyes. "I'm fine" he mumbled weakly again.
The third to come was their homeroom teacher. Aizawa entered the crowded room, concerned eyes searching for Midoriya. "What is it with the problem child?" He asked quietly, noticing Izuku's semi-conscious look and his shivering from under the blanket. "He has a 39.2 c fever, and threw up yesterday's meals" Tokoyami said in a stern voice, eyeing his classmate. "Great" Aizawa sighed, turning to face the three standing teens.

"You three did great, now go to your beds and sleep until you need to go to class. I'll take it from here" said Aizawa. The others nodded and went each to their own room. "Problem child, are you awake?" He asked quietly, and to his surprise Midoriya answered "I'm fine, you don't need to stay". Izuku tried to sit up, but a long coughing fit interrupted him. Izuku searched for his tissue box with his eyes, and before Aizawa got to say anything the boy sneezed into the crease of his elbow. Aizawa handed him a tissue and glared, while the sick boy wiped his nose silently, still shivering.
"Clearly" Aizawa said finally, and sat on the chair next to the desk. "Aoyama said they found you laying here on the floor, and then you ran to puke in the washroom. You have a high fever and I believe it is still rising, hence the shivering. You cough like your beloved All Might, pale as a ghost. Clearly you are healthy". The boy tried to look at him through his glassy eyes with determination, but to Aizawa he just seemed like a tired, lost kitten. "Go to sleep" said the teacher, and looked at the clock on the night stand. "I'm going to make myself a cup of coffee, and a cup of tea for you. You will stay in this bed and rest until I come back."

On his way to the kitchen, Aizawa met a concerned Todoroki (looks exactly like the every day Todoroki, but with a tiny crease between his eyebrows) in the corridor. "What are you doing here?" asked the quiet kid. "I could ask you the same thing" Aizawa answered, "your room is on another floor". Todoroki looked down for a second before responding. "Midoriya was not outside on his usual morning jog, so I was worried" he finally said, looking at his teacher once more. "Yeah, problem child has a fever, better let him rest for the day. Go to bed or go to class, but don't come into his room" the tired man concluded the conversation, walking again toward the kitchen.