Hi, I have had six concussions over the course of my life and multiple head injuries. Having several close together as you have, I believe makes it hard for the brain to recover. In my case, after 9 years from the last concussion, my symptoms have not improved. However, I must say that I have always pushed myself very hard to perform physically and mentally.
The one thing I have found that ALWAYS increases symptoms is STRESS.
No matter what else you do, try to dramatically reduce stress. As for the rest of the "triggers" I just view it as part of my life now, as when in the past I would hit it hard in some activity and felt sore or exhausted. I have to view my changed condition in this same way, when I overdo things I will get tired, takes longer to recover, but I try to gauge the benefits and enjoyment of the activity with the side effects and make the decision beforehand as to whether it is worth it.
I am not offering much hope, but you can survive whatever adversity you encounter by keeping focused on all the positive aspects your life offers.
One of the more positive results of my condition is that I am more empathetic of those with various disorders, especially when they are not physically apparent. I used to think people were just lazy or weren't trying hard enough, but now I realize that everyone has limitations in one thing or another.
Happy life to you..

Tony