Vitamins like folic acid...?

alright we were a little indecisive about children...I had been taking my multivitamins for several months (including the 800 mg the doctor prescribed) but one day I decided to stop, since husband wasn't 100% in and I gave up, I KNOW I KNOW I should have kept taking them no matter what, well now we've decided to start "trying" we don't know how long it will take us but I just started taking the vitamins again. The doc had said "take them everyday, not like one day you take them and the other one you don't, but EVERYDAY! for at least 3 months prior to conceiving"...well now I'm afraid if I get pregnant right away and I haven't really taken them for that long this time...is it a problem? should I prevent a pregnancy for at least 3 more months or so while taking the vitamins?