Pre natals after 12 weeks.

Hello! I've obviously been taking my pre natals with folic acid since finding out I was pregnant every day. I'm now 12+2 and I'm wondering do I have to keep taking them? I wouldn't mind but I feel that they really upset my stomach, I take it before bed every night and wake up with diorhhea religiously every morning and I genuinely think it's being caused by them! Can anyone help or is in a similar situation? Xx