Berat x naik2..

Hi all. I'm on my 24th weeks now. The problem is that I keep loosing weight (~2kg) since my 1st check up on Dec last year. My last check up was on 15th April, by then I'm able to gain a little around 500g. So is it okay to puasa? I tried to fast today, but I'm starting to get dizzy around 3pm. This is my first baby.