I'm at the three-month mark post-concussion. I had a good half-dozen setbacks during the first two months where I got slammed after feeling better and doing too much. So I totally get what you're talking about.

Things have improved over the last month or so. Over the last 3+ weeks I've had no setbacks and seem to have more of a stable "floor" underneath me. However, I've taken things pretty slowly - we'll see how I respond as I gradually increase my activity level. I still have a fair bit of room to improve on the upside (I'm probably around 70-75% overall).