If you have trouble returning to work, you need to continue to rest. It would be best for your brain if you could return to work with zero symptoms - especially if you still have some FMLA time left.

I was unable to wait until I was symptom free to return to work. I returned to work a little over a year after the concussion I sustained.

I still experience symptoms and I'm not all better yet and it's now been 20 months since the accident that gave me a concussion. But I sustained a concussion with some rare complications.

Mark In Idaho has said in previous threads that the more symptom-free days that you can string together, then the less time it will take you to recover from the injury and the better the recovery will be. I think he's right. Try to string together a week of symptom-free days before returning to work if you can.