Late Period,,,

​I decided to get off birth control as I am 22 now & have been on it since I was 11. (Before anyone has anything rude to say, keep it to yourself. I was NOT sexually active at 11. & that's not why my mom got it for me. I had awful acne, extremely heavy periods, & my mom didn't want us to be afraid to talk to her when we (my sisters & I) did decide to become sexually active & then it be too late). Anyways, I was on the pill at first but got flu like symptoms. Then, at 16 switched to the shot. Was on that for a few years, but then my mom had friends who had trouble getting pregnant & didn't want that for my future. Next I had mirena. My mom never thought my doctor would approve that since I don't have any kids, but she did. It was great for about a year & a half but then my body reacted weird towards it. I was having pains that my mom compared to contractions. Like my body was either rejecting it or believed it was pregnant. I got that removed & started the nuva ring. But after some thinking I decided I wanted to give my body a break from the pharmaceutical hormones. So after my second nuvaring cycle, I never put another one in. Two weeks later, I had to take the morning after pill as a precaution of some drinks with my boyfriend. (We be been together for 6 years. We know the risks & are taking precautions minus me being on something). I started bleeding a week later (which has never happened when I have taken the morning after pill before). It's been 4 weeks since that bleeding & 6 weeks since I had the cycle from my nuvaring. I've taken 3 pregnancy tests (this morning most recently) & all are negative. What else could be causing my late period? Could I still be pregnant? What should I so next?