My obsessions are like a game, I lose parts of myself

I live in the suburbs with my parents and two sisters. My dad always fights with my grandma, calling her out on the smallest things, saying she never does things for him. For some reason, I become fixated, obsessing over that fight, trying to 'solve' it. To 'solve' it, I essentially find a way to justify it. But until I do so, I lose parts of me. While I'm trying to 'solve' it, I can't function as clearly; my sense of humor begins to fade, even though I don't want it to. It's like I'm stuck in my head, like a weight is on it. Sometimes I feel like I lose bits of my intelligence too, not able to write as clearly and function well. What do I have? It feels like OCD to me, but once I 'solve' the fight, my symptoms disappear, until I fixate over another one they've had in the past.