I used to have these experiences for years....let me give you a tip though, anti-psychotics are not effective at stopping them. Anti-psychotics make you so sleepy u cant do anything. On top of that they make it worse!
Its your own mind playing tricks on you. Learn to focus your mind..

If you suspect that youre being harassed by spirits it may be useful to learn protective magics. Or if youre christian..umm...hell i dont know what christians do any more haha