Feeling defeated by math proofs

I'm a grad student in physics who wants to do another master in pure math in the future. I've been self studying algebra topics in my free time (did most of a pure algebra curriculum on my own), most of my extra courses in the bachelor and master were math related and I spent some time teaching myself number theory, category theory and some other niche topics. I can understand advanced math and complex proofs. I just can't seem to think with my own brain. Today I was reading the first pages in the second chapter of Algebraic graph theory by Godsil and Doyle about the orbit stabilizer and the asymmetric graphs theorem. I go slowly but understand stuff. Then I move to the exercises. Blank. Since I was little I was always told I'm more fit for humanities, and I know that myself too. I still struggle to make this math thing work because I find great joy in it, but as the days pass and I notice my inability to improve my logical and proof writing skills, I can't help but wonder if I should just resign to keeping math as a hobby. I'm not really unhappy about this (obviously I would prefer to be a genius and understand everything on sight, but I don't really blame myself for not being as capable as others), I'm just reaching a point where this logical conclusion has been fully formed in my mind. I just wanted to ask you people if you have any good words of advice. If you were in my situation, being fully realistic, would you keep on trying or opt for more reasonable and grounded career choices? Do you ever feel like math is not clicking fast enough in your brain?

Author: ilpendolo7