Most of the symptoms you reported (heavy, painful prolonged periods, eratic cycle, pain during intercourse, pelvic pain/burning, fatigue) might be related to hormonal imbalance. No data was given whether the laboratory tests included sex hormones.
If the reason for your condition is hormonal imbalance, then products containing hormones (Provera being one of them) might be helpful.
The chances that the tumor was missed, if the biopsy was ultrasound guided, are very small.