Highs & lows

Yes. Your body has been through the trauma of the surgery, you'll be dealing with new pain too that you are not used to - different from the OA pain. Also it is quite normal to be pretty anxious and apprehensive before surgery and afterwards as the body slowly heals, and it often feels like two steps forward and one step back in the recovery process, which can feel disconcerting. As you are struggling with negative memories from your past it may be worth talking to your GP about it, which may help to put your mind more at ease.