I haven't had my period for about 6-7 months and I thought it was cause I came off birthcontrol but…

I haven't had my period for about 6-7 months and I thought it was cause I came off birthcontrol but it still hasn't came also for the past two weeks my breasts have been hurting badly and my back and waking up with headaches and little weird pains here and there. I have taken a home pregnancy test and it said negative and the at the Health Department they said the same. What should I do or what do you guys think it may be?