sad, depressed, need advice :(

I am currently engaged and pregnant (17 weeks). Lately all I do...and all I want to do is cry. I feel so ugly, and unwanted. I feel like my sex drive is through the roof but my fiancé doesn't really find me that attractive anymore (even though he says I look fine). I can tell, before he wouldn't be able to keep his hands off of me, and now we could go days without sex. He's not scared of hurting the baby or anything like that, so that leads me to really believe that it's me. I used to be 115lbs when he met me, and now I'm 158lbs - I've only gained 5lbs this pregnancy but I feel like now since my belly is showing a little bit...it just makes me look fat. I'm breaking out like crazy too. He gets annoyed by everything I say and everything I do. He used to like to pamper me but now he doesn't really care. Yesterday I asked him if he could put on my stretch mark lotion (he used to like it), but these past times he just gets mad and irritated when I ask, so I've stopped. I cried myself to sleep right next to him. He also said he misses his kids (from a previous 5 year relationship) so Idk if he's getting frustrated because of that. In my head it makes me feel like he wants his baby mama back even tho he has had no contact with her but idk right now I am so sensitive and the worst things come to my head. We've been together 2 years, engaged for 1 year and planned this baby. I'm so sad. I just want to die, I am so miserable and it doesn't help that we always fight because he has such a short fuse. please help, any kind words would help.