I feel guilty

My partner has pmdd and she has worked so hard on it, but the period leading up to the period is just getting too hard for me to deal with. I feel I'm loosing touch of myself, I'm feeling more and more alone with the relationship and just in life. We have been together over a year now and I can't find ways to deal with the polar opposite of her during her pmdd.

I want to leave her although I feel guilty because she has tried to hard to control herself and I have tried hard myself in learning more around hormonal changes yet i fear, if this is what life will be like forever more in a relationship then it will slowly take me away from being myself.

The other part is when she is on her good week and a half and over feeling guilty for being in a depressive state then we share such beautiful moments together... which is why leaving her makes me feel incredibly guilty.

I dont know if I'm after advice. I just figured venting this to a group that has more of an understanding then my mates might be a good place to start.