I Was On Sprintec For Over A Year And My

I was on sprintec for over a year and my prescription ran out while at college. I ended my period November 28th and haven't had one since. I was put back on birth control and was told that my body would take up to 3 months to regulate again? Is this true. I feel as if I'm going to start, cramps mucus etc I just haven't. I am not necessarily sexually active, the only thing I've done was I was fingered in December. Thank you for you help, I'm nervous. Should I be ?