hi mumma! congratulations! to answer your questions,
1. yes, you can expect a bit of cramping. as long as it is not accompanied by heavy bleeding, you're fine :)
2. you would usually see your gynae at 6th or 7th week as it is too early now and can only see gestational sac
3. you can start taking folic acid, the earlier the better. as for the prenatal vitamins, my gynae only gave me those on my second trimester
take care!