Hello,
If you are not having a regular period then it becomes difficult to know when to test. So if you are trying to get pregnant you could test randomly or if you notice the onset of early pregnancy symptoms (e.g., breast tenderness, nausea, fatigue, frequent urination). If your goal is to get pregnant, given your history, I'd suggest you see an ob/gyn to discuss this further. Because you won't get pregnant if you are not ovulating (the ovary producing an egg, also called an ovum) and they can discuss with you (based on your history) how you can maximize your chances of ovulating.
Best regards,
Dr. Downing
Also, is it posible to get pregnant if I haven't gotten a period in that long?