My brother have bad intentions on me!

I'm 28 year old women, and I have been living in tier 1 city along with my brother, as i’m preparing for my govt. exams. My brother is a 17 year old boy. lately he has started behaving very weird, though he has a separate room but he comes n sleep beside me very often. That makes me really uncomfortable at times. Sometimes he hugs me which was normal earlier but now a days it feels uneasy and I can completely sense it. The thing is I know what is on his mind but I don’t know, how to make him understand that its very wrong. I can’t even talk to anybody about it. It will really create chaos in the family and above all my preparation for the exam affecting a lot. I cannot focus on the studies. Though I go home only to sleep & the rest day I spend in the library. But I’m really scared to go home these days. Idk what to do....