I want to leave him, but I REALLY don’t.

I’ve been with my boyfriend for three months, and I really like him and want to continue our relationship for as long as God wants us to be together... But having bipolar disorder is making it hard. I’m stably medicated, but because of my cycle I can still get depressed since my period tends to almost cancel out one of my meds. Once a month, I go through short phases of time where I want to leave him, just because of trivial things like the way he looks from certain angles. It’s ridiculous. I know I don’t want to leave him, but sometimes it (depressive episodes) makes me feel so upset that I don’t want to talk to him at all. I think that I need to tell him this in order to continue our relationship in a healthy manner, but I don’t know how to without it sounding like we need to break up. Help!!!! Please??!!