Why do i feel like everyone's better then me?

18yr old male, idk why i been feeling like this....for some reason i just feel soo out of tact with myself...idk why but its really weird...like i always feel that my friends or someones talking about me, lookin at me in wierd way etc, i just feel weird...and the weird part is, all this didnt start until i broke up with my ex gf last year (1st love)...(yea i kno pathetic) but is there anyway to stop this?? like its startng to show