Does the dispute that occurred between my friend and me constitute an estrangement that prevents deeds from being raised in Sha'ban, knowing that I suffer from obsessive-compulsive disorder?

There is no blame or sin in shunning someone who harms you. This does not preclude the promised reward for one who abandons animosity. Shunning ceases with a greeting. So, if you meet the woman, greet her and keep the relationship superficial to the extent that it does not cause you harm. As for obsessive thoughts (waswas), you must repel them and strive to rid yourself of them.