How come people say I do things which I don't remember doing?!

How come I feel different all the time?

Yesterday I was shivering in a corner feeling spiders crawl all over my body and screaming as a dead person was talking to me.

Today I feel fine? It's like weird stuff happens and I remember it but it's all distorted and unclear.

I get really paranoid sometimes and then the next day I am relaxed and normal. Please help they are telling me not to tell my psychiatrist... My psychiatrist isn't my real friend they will probably lock me away forever and poison me or something