I second the idea of keeping a daily log. I wish I had done that since the beginning of my concussion, but I started to keep a video log on my computer every day for the past two months or so.

Unfortunately for me it hasn't helped in detecting any actual patterns, as my symptoms seem to be randomly better or worse on any given day regardless of what I've been doing. Sometimes there isn't any clear patterns, but regardless it's nice that if you're experiencing something that was similar to a previous day, you can check back on your log and see if there was any similarities to those days. Just avoid doing it if you're going to constantly obsess over it though, as I feel that might hurt more than help.

Still, it could be helpful to see if you're doing better on days where you're resting a lot vs. pushing through it.