I need serious help!!!! its pretty much ruining my life!!!!?

I have major depression, i take Celexia for it. but the problem is, it doesn't seem to stop it! every night i get majorly depressed, and i think everyone hates me, including my boyfriend, who tells me he loves me everyday. i look at his facebook and see all these chicks saying i miss you to! and i get really jealous for no reason (i'm usually not like that) and i start going crazy and thinking hes cheating on me and i start crying cause i don't wanna lose him, and trying to remember the promise he made to me about being faithful, thinking he secretly hates me, not believing him when he says he loves me, and than, after an hour or in the morning, my mood goes back up to normal. i get all snappy and depressed, i start crying because i think everyone hates me, i think i'm fat, i think i'm ugly, and it happens everynight!!!! its pretty much seperating me from those who i love and who loves me (which i believe is nobody) and its just crazy! whats happening to me???