What Causes Hair Fall After Having Complete Hysterectomy?

okay had a full Hysterectomy 2012 and since then my hair has been breaking off in hand fuels. No bald spots it just keeps breaking off and I feel like I m missing something a vitamin maybe a some kind of supplement. Am I correct? I did have a gastric bypass in April 2005 and have never really had any complications from it... But the hair breakage is took much I need to fix it. And I do no want to cut all my hair off again. Is there any answers for this because I fully believe it has to do with the hysterectomy I had???