I've been very scared of hitting my head again, I had one concussion and then hit my head again a month later but I don't think the second impact was a concussion (is it 'easier' to get a concussion when you've had one already? Is your brain more sensitive to them?), however it is since that second impact that I developed all my symptoms.

This means I'm scared of even the smallest bumps, but I'm also horribly clumsy and really careless (obviously I'm only aware of this after I've done something careless) since the second accident which means I think I'm more likely to get hurt too

The second accident was a really minor car crash where someone went into the back of my car so I'm scared of having another accident like that and that sort of accident is unavoidable.
I've found I'm much more anxious in other people's cars. I now brake very early as I'm over cautious and most people don't brake that early so I feel like we're going to hit the car in front when there are others driving. I sit in the passenger seat clutching the seat with my foot pressed down hard in the foot well as if I can somehow brake!