No period

So here’s the thing, I know this sounds like I’m pregnant but I’m really not. Im not sexually active due to a knee and back injury that I had surgery for and I’m in physical therapy and it’s too painful to do it. But my breasts are extremely sore and I often get almost like shooting pains, and on top of it I haven’t gotten my period in over 2 months. Any idea what could be happening? I haven’t had sex in at least 8 months and it kinda has me freaked out that it’s happening. Suggestions? Thanks.