Whats going on with my body

Ok so I have been having this weird peroid for te last couple months where im spotting and stuff and I have severe cramps like im gona get ready to start my peroid. Now I have been on birth control for almost 4 years. I dont have any signs of being pregnant but I do have some signs of having a miscariage. but when im off my spotting the cramping stops and everythings normal. My lower back hurts and I try to curl up in th efetal position and that doesnt seem to help. Whats going on with me am I pregnant or am I having a miscariage???

Do a test if you are pregnant or having a miscariage then it should still show up. If you are miscarying you should get to a doctor asap. Good luck

id say you should get tested for Polycystic Ovarian Syndrome...
weird periods are the most common thing with that