TTC with irregular periods


I'm hoping someone can shed some light on my situation...ever since I came off the depo injection over a year ago I've had irregular periods which has made it very difficult to conceive. I ovulated for the first time this month in 13 months!! AF was due 4 days ago, and still no sign or no symptoms of it arriving. However, how long should I wait before I should test? My periods are very irregular anyway so should I even be expecting my period to arrive? I can go months without a period. I have no signs or symptoms of pregnancy. Do you think I should test? I'm not sure if I can face a negative test. Anyone got any success stories of getting pregnant with irregular periods or when coming off the depo injection? Any stories or advice would be great!