The symptoms you list are all part of depression. They may exist in the brain injury community but it is difficult to say whether they have a cause other than depression. Your rumination about what may be is counter to your improving health.

In the US, there are 5 million or more concussions each year. But, life goes on. Very few cause any substantial prolonged symptoms. Since you symptoms are depression oriented and do not include any symptoms that are specific to brain injury, I suggest you try to move on with your life. Focus on recovering from your depression and the rest will be fine.

It is important that you resolve the use of this med that causes you to feel lightheaded. Falling down and hitting your head will eventually cause trouble, especially if you do it repeatedly.

So, trust your doctors and deal with your depression.