I didn't really take my prenatal vitamins past 7 weeks

Is that bad? I mean, I know the risks of spina bifida. I just was so sick. Even with the medicine they prescribed, I was too sick to take them. Im about 12 weeks now and have started taking them as much as I can again. I'm so scared. And I feel so guilty. I was getting so dehydrated and sick from puking constantly. We have no history of ANY defects in either of our families. Should I be worried?