ttc and overweight

I have never been this big before. I have been trying to get pregnant with our third for a year 5th round of clomid. while on clomid I'm also trying to loose weight. drinking a ton of water I mean like 1 and a half gallons of water a day. no weight has been lost. if I could get pregnant I loose weight like crazy! I totally hate my body and myself and am so down. I don't ever open up like this either. I am so desperate to have one more baby. it will be a c section with a hysterectomy if I get pregnant so it will be our last