Week 7 post endometrial ablation and still having bloody discharge, why?

Ablation. Most women experience discharge and spotting for several weeks after an endometrial ablation. 7 weeks of discharge is not common and is probably not normal. I advise you to contact your obgyn with your concerns. I would recommend an exam and possibly ultrasound to see if there is evidence of infection or hematometra, which is are rare complications of the procedure.
This is not uncommon. It is not uncommon to have some bleeding after an endometrial ablation. In some cases regular periods may return after several weeks to years. It is more common to have light bleeding. You should discuss this with your doctor at a future visit. It is not urgent.