Traditional end of the semester panic

I have been trying to write this paper for days and I cannot seem to get it out.  I am having a really hard time with this class.  I am afraid of turning writing in to this professor and I don't entirely understand why.  I want to write this piece and I think that I have finally figured out what to write it on after reading all of the options more than once.  But I still don't feel that I have any valid thoughts on this piece.  At least not that I can expound upon for 1000 words.  I wish that I could write him a paper on why I can't write this paper.  Critical Analyses terrify me. I emailed my professor and he said that he would be in his office all day, so now I simply have to find the courage to go down there and talk to him.  I don't know that he can help me.  I don't know why I am freaking out about this as much as I am.  I am starting to think that I may need to try to get medicated, because this cannot be how life is for everyone.  I cannot accep that.  But I am also not thrilled with the prospect.