My girlfriend has epilepsy and is taking Topamax medication for it. But I'm worried about her…?

She suffers memory loss, becomes really upset, aggressive and hostile towards me over things that we should be able to sit down and talk about. I have been blaming myself for upsetting her but it's like she turns into a different person when she's upset and it scares me. She loses her temper when I upset her unintentionally and won't listen to me or calm down. It upsets me and worries me because I love her and would never dream of hurting her intentionally. What do I do? We have broken up twice already, it's like I'm treading on egg-shells and I don't want to lose her forever…