I recently had an endometrial ablation. at the time of the ablation i was on ocp. my surgical note says anteverted and anteflexed 8-week sized uterus, atrophic cavity, normal tubal ostia bilaterally. is this normal?

Yes this is normal when taking oral contraceptive pills which keeps the endometrium minimal in size as part of its pregnancy protective method.

An enlarged uterus (to the "8 week size" of pregnancy) may be secondary to either "fibroids" or "adenomyosis". Ask your GYN physician about resuming "OCP" as such will stop ovarian estrogen, which is higher after 40, and hopefull prevent the necessity for surgical removal of the uterus.