Implanon expired but wanting to conceive?

I had the Implanon implant inserted September 13th 2012. I have a hectic work schedule and can't afford to have it removed at the moment but my boyfriend and I are trying to conceive. I've had numerous symptoms and have taken a few pregnancy tests, all negative. I recently had a very short period (5 days) which is not normal nor the little amount of blood i had. How many months after it expired would be the best time TTC?