No period for over 2.5 months

So I haven't had a period since October 9-13 (2 weeks before I was sent home from air force basic training). I haven't been super stressed since I've been home from Texas and expected that my period would show up within a month of me being home. Nope. Never happened. Then 3 weeks ago, I developed period type symptoms (cramping in uterine area and back pain), so I put a pad down and started carrying tampons. Still no period. A week after the period type symptoms occurred, I developed a throbbing type pain in my right ovary that feels like a dull knife is continuously poking me and the pain varies day to day. Some days the pain is a level 2-4 on the pain scale, other days it's a level 5-7 or so and otc pain meds don't help. I had an appt with a female PA at my doctors office last Friday and she isn't sure what's going on, so she referred me out to get an ultrasound (done yesterday) & it looked like something might be there but I am not sure since my neck was at a weird angle, so I have to wait until my appt with my new OB/GYN in a few weeks to be scheduled for further tests. Also, all pregnancy tests have been negative and I have the nexplanon implant and I've never had any issues like this before. 😔😔😔😩😩😩