I have not had a period for a long time now since I started taking prenatal vitamins I have my period again so now can I get pregnant?

Period. I don't think that your prenatal vitamins were the cause of it Starting again I think I would see a gynecologist to find out why you had no and if you are still able to get pregnant.
Possibly. Women, who have regular menstrual periods in all likelihood ovulate and therefore can become pregnant.
Need evaluation... If you aren't pregnant already and are not having periods, you need to see your Ob/Gyn for an evaluation. There are a number of things and can prevent you from having regular periods and it will take some testing to determine what is going on in your specific case. Pre-natal vitamins won't keep you from having a period. Best wishes!
Maybe. There are many reasons for having irregular periods. Sometimes there are reasons that prevent you from becoming pregnant. If you've had a period then there is a chance that you are ovulating and hence a chance to get pregnant. If you don't after several months, consult a fertility specialist.