How should i deal with this???

i have a friend who is hard headed. he just bugs me and every time he would talk to me during cl i try to ignore him because there was already 2 days that i didn't finished my work and i didn't like that. what i am trying to do in cl is to get good grades but in my opinion he is just trying to stop me getting a good grade. there was another day that i did miss the homework because he was talking to me. lately i've been noticing the real him. last year we were just cool and everything. this year since he is in my cl, he is very nosey. there was once he just comes out of nowhere and checks what is in my bag and i didn't noticed. another time was i was helping someone with their laptop in cl and i left my email open. when i come back i caught him looking through my emails. i already don't trust. what else should i do? he even wrote a letter today telling me all the stuff that i do to him and not everyone else. don't say that i should tell him that i need space.