help?

So the past few weeks I've been having bad cramps, like period cramps, but no period. It's now turned to that constant dull ache like I have my period. It kills! But all pregnancy tests are coming back negative.. should I talk to my doctor and see what's going on? I messaged her and asked her if I just need to jump start my period (been off implant for over 2 months, but haven't had an actual period for almost a year) any advice ladies??? Could I still be pregnant and just not showing on tests?