Advice needed, especially professional...

In 2013 I got the Mirena IUD. In 2016 I had it removed as a trial-and-error test because I'd been having chronic migraines that my doctor couldn't find the cause of. Long story short they went bye bye with the IUD. I've been in along distance relationship so sex doesn't happen often for me. Last time I'd had sec was in June and I got my IUD removed in august. After removal my cycle came on the last day of the month and was off by the second of the next month in August, September and October. It went off November 2nd. My fiance was in town for turkey day. I started bleeding on the 22nd and freaked out. My period has NEVER been that unpredictable. However there was no cramping or acne like usual. Although I was cramping something serious after the bleeding stopped. It lasted 4 days and there was a repeat in December. I wasn't sure what was going on with my body so I took severe hpt just cause. I had 4 negative results, 2 faintly positive results, a negative urine at my GYN, and a negative hcg blood test. I've been nauseous daily, more tired than usual, I get random and extremely painful cramps, I don't think I'm pregnant however my body only felt like this when I WAS pregnant. I have 2 other children, and didn't bleed during either pregnancy. I'm truly at a loss on what I should do because I'm having a hard time functioning these days. I've even consider the fact that maybe my body is readjusting after going without sex for so long? Even though its never happened before and I've gone longer with out it. But I haven't had sex since thanksgiving holiday and nothing with my body has changed....