This can be just a relapse or decompensation from your original concussion or it could be a second concussion. It is not Second Impact Syndrome. SID is when the brain is concussed again but has not recovered the ability to regulate blood flow in the brain since the first concussion. This allows an increase in blood pressure in the head to the point of deadly consequences.

You may be heading into Multiple Impact Syndrome but I doubt it. MIS is when the brain has been impacted so many times or enough times with enough damage that it has lost much of its ability to recover. It is the reason that anybody who has suffered a concussion needs to seriously consider life style changes to avoid the impending next impact. Believe me, they will happen even with lifestyle changes, just not from soccer or football or such.

I suggest you lay low like you did the first few weeks. If things get worse, you might contact your doctor, especially if you sense an increase in severe head aches and troubles with vision or such.

Before you car accident concussion, your bump with the door would not have been much of an issue beyond OUCH. Now, you should understand what is meant by those of us who warn against taking risks of further concussions. Sorry you had to experience this second head trauma.

My best to you.