I have bacterial infection since i first conceived have taken many antibiotics but it keeps coming again&again, what to do?does this cause weight gain?

Possibility: Often, recurrent vaginal infections may be caused by an asymptomatic urinary tract infection in the sexual partner. If this is a possibility, have your partner checked. Good luck.

Have partner checked: You may be re-infected. You say you have conceived, so weight gain may be due to pregnancy. The infection and antibiotics would not cause weight gain.