I'm pregnant an losing weight like crazy?!

I usually weigh 123-126 is what my average is I'm 5'4 so it balances out and surprisingly I have a big butt an I'm not trying to lose that during me losing weight an I wear a bra size of C36 not big but surprisingly for me being a smaller girl u could say . I was kinda excited to be pregnant cause I've never been over the jean size 3. Well little did I know first trimester all I can take in is water I drink a lot but manage to puke that up! I puke anywhere from 1-4 times a day usually 2 I was 122 when I got pregnant now I'm almost under 115! Like what! I try eating little a day an nothing works everything comes back up I though I'd be able to put on a few pounds not lose them 😕 tips please