I just realized that my vitamin doesn't have iodine or choline and I'm 15w3d pregnant. What can I do to compensate for this time not taking it?

Not an issue. I am not sure where you are getting your information. You can simply buy any over the counter or prescription prenatal vitamin which will have more than enough of anything you need. You could also just add more fruits and vegetables to your diet. Folic acid is important before and the first few weeks of pregnancy. After that vitamins have a very limited role.