Idk anymore

So, I stopped my birth control in June. Had my period in July. August rolls around and no period. I went to my doc and they said that that's normal, it's just my body trying to get back on track. September rolls around and I didn't have my period this month either. But the past could of days I've felt SO TIRED, achey/heavy boobs, and now my upper legs are so sore and some cramping in my lower abdomen. What does this sound like it could be? I wanna take a pregnancy test but I honestly don't know if it would even be accurate because I haven't had s period since July.