Welcome to the EmpowHER community! Thanks for your question.
The on-and-off spotting could be your body still getting used to going back to a regular menstrual cycle, though it usually takes about three months at the longest. However, if you had irregular periods before birth control, it is likely that they will be irregular again after going off of the pill.
You should be able to get pregnant once you begin ovulating normally. That said, most couples take up to a year to conceive, so you might just have to wait it out.
Of course, your doctor will be able to give you more personal, in-depth answers at your appointment. Best of luck!