Stuck

What did I do?

I woke up feeling terrible. I had a headache and every bone in my body was screaming in agony. I tried to move but my muscles wouldn't allow it. I didn't like it, I don't like feeling helpless, to be alone. Then I heard a voice.
"Dipper! Your awake!" I winced at how loud it was.
"Oh I'm sorry, I didn't mean to shout. But at least you're awake now. Can you talk?" They asked me.
"Yes."
"Can you move?" I tried once more to move and found it was a bit easier.
"Kind of?" I responded.
"Can you open you're eyes?"
I opened my eyes and was startled at how bright it was. I looked around and noticed I was laying on my bed, the one in the attic. I was back in the Mystery Shack. I don't know why, but I felt a feeling of disgust start to form in the pit of my stomach.
I turned my head towards the voice and saw my sister.
"Shooting Star?"
She seemed confused.
"Shooting Star? The only person who calls me that is..." She looked at me, alarmed and then screamed. She jumped backwards with a look of fear on her face.
I didn't know what I did wrong.
"YOU EVIL NACHO! WHAT DID YOU DO TO MY BROTHER!" She screamed at the top of her voice.
I sat up and looked at her, clearly confused.
I was about to ask what was wrong when I heard running coming up the stairs, then I saw someone bust through the attic door. It was Ford, I felt a smile cross my lips.
"Mabel what's wrong!" He shouted.
"ITS BILL! HE POSSESSED DIPPER!" She yelled. He looked at me and I could have sworn I saw a look of fear on his face, but he quickly replaced it with something else. He took out a gun and pointed it at me.
"GET OUT OF MY NEPHEW YOU ISOSCELES MONSTER!"
"Ok what is going on up here." I heard some else say. I'd recognize that voice anywhere. I saw Stan walk through the door and take in the scene.
"FORD WHAT THE HELL ARE YOU DOING?!" He shouted.
Again with the screaming.
"Stanley stay back that's not Dipper." Ford said.
"Ok everyone calm down. Put the gun down, Sixer." I pleaded.
"See he called you Sixer! It is Bill!" Mabel told Ford.
At this, I was confused.
"Why would you mistake me for Bill? Isn't he dead?" I asked.
"Rude much Pinetree?" I heard myself blurt out.
After that the room fell silent.
"Dipper?" I heard Shooting Star call me as she approached slowly.
"What?"
"Are you ok?" She asked.
"I'm fine, why?"
She didn't answer me, instead she looked at Ford who gestured something both to her and Stan.
"Mabel, Stan...may I talk to the both of you...downstairs?" He said putting his gun away and gesturing to the stairs.
After that both Shooting Star and Stan had left the room with Sixer, leaving me by myself, wondering what I did wrong.