What info is relevant when logging migraines

Got hit by a car while on the back of a motorcycle on Christmas Eve and have been suffering about one migraine a week since (roughly). I spent all day yesterday and today in bed, puking intermittently. I wish I had been recording my migraines from the beginning, but have started to now. I just can’t imagine what would have triggered this one because I was inside pretty much all day on Monday and only went out to get food at a coffee shop, then my head started hurting. What kind of info is relevant when logging migraines? What I ate, whether I slept (I have insomnia), where I went, all seem obvious but also haven’t given me an answer to what is triggering them. I’ve had migraines before caused by either heat or not getting enough caffeine, but now they are a regular part of my life and I really hope there is something environmental that’s causing them that I can control.