go over (something) in (one's) mind

To think about something, perhaps to understand or make sense of it. I've been going over our exchange in my mind, and I still don't know what I said to upset her so much. Hey, can you help me with this? I've been going over the teacher's instructions in my mind, and I still can't remember what to do with equations like this Would you please stop ruminating? I know you're going over everything your ex said in your mind right now.

go over something in your ˈmind

think very carefully about something that happened to you: I go over that terrible moment in my mind every day.