I ate something wrong and now i have gas and loose stool, not very loose but anyway. pregnant 32 weeks how can it harm baby?

Not a bit: If you are gassy, it's more likely due to chemical reactions or lack of enzyme activity in your colon. The issue doesn't enter your blood stream, and won't cross the placenta. It only affects the baby in that if you feel uncomfortable, the steps you take to relieve it, or if it keeps you from doing other things to take care of yourself.