If I've gone a couple weeks without taking prenatal vitamins but would like to try again and start up again, is that ok? Considering I hadn't been

Absolutely. The data shows that prenatal vitamins should be taken before pregnancy to decrease the risk of spinal cord abnormalities in babies. Most women in the US have an adequate diet, but 50% of pregnancies in this country are unplanned, so yes, you can restart the vitamin. There is no "withdrawal' if you stop suddenly, and no risk (other than stomach upset if you had any), to restarting.
Ok. Why you did stopped them? Any medical reason or just forgot? Ok to restart taking them but do not take excessive dosis to compensate the lack of them in the past.
Yes. I don't see any reason why you couldn't start taking prenatal vitamins just because you didn't take it for a couple of weeks. If you are pregnant, you should at least be taking folic acid.
Yes. If a woman is pregnant, it is important for her to take prenatal vitamins as the prescription was originally written by the prescribing physician. If some are missed, there is no safe way to "catch up" so informing the OB that 14 or so were missed and taking supplements as directed would be important.