Hi. I had a total hysterectomy around a year and a half ago. (Endometriosis) I am also in my 20's. I haven't really gained a lot since the day of my hysterectomy, but I do find it harder to lose and the weight loss is much slower. I can't eat as many calories as I used to and still lose. I can't eat as many refined carbs or sugar. And I have to be really strict about it, I used to be able to go off plan a couple of days a week and still see loss, but no more.
As far as hormones, that's a bit of a science. Even if you take hormones, you could be out of balance, it could be the wrong delivery method for you (pill, patch, ring, cream) or you may need additional hormones (progesterone, dhea, testosterone etc.) Have you had your hormone levels tested? I had to find a hormone specialist after my surgery, my old gyno wasn't as great with hormones as he was with surgery and delivering babies.
Have you been to www.hystersisters.com
it's a very supportive helpful community.
Weight loss can still happen for you, but it's going to be harder than before and there are more factors at work.