Sayang, diarrhea + nausea at 33 weeks could be a few things, definitely mention to your doctor or midwife asap, okay? Better safe than sorry, especially when pregnant. A couple of mum friends had gastric issues at this stage, tapi some needed checking in case it's something else. How are you feeling otherwise, any other symptoms? Jangan delay, just get it checked out to be sure everything's okay with baby.