Endometrial ablation

Hi I was hoping to post an anonymous question please.

I had an endometrial ablation approximately 6 years ago due to years of endometriosis despite surgery to remove it.
Since the ablation I have had no bleeding, however in December I started having extreme pain that lasted for two days and then nothing, it happened a month later and the next day I had bleeding not much but pain disappeared, it has happened every month since.
My doctor sent me for an ultra sound and said it is all good, my recent Pap smear is also clear. My doctor now wants me to have another ultra sound and go to a gynaecologist.
She said in my last ultra sound my endometrium was measuring 8, is this normal after an ablation?
Was hoping to hear if anyone has been through anything similar and what happened?
My doctor has told me not to worry it’s nothing bad but I am worried.