Hello,
Thank you for your query at DoctorSpring.com
I understand your concern.
It seems mostly due to anxiety, and moreover the injuries that are possible secondary to trauma, such as hemorrhage would have been detected by now. However, i will recommend you go ahead and get a MRI done, because it is definitely the best investigation modality, and can pick up if something is wrong.
In case it do comes out normal, then you will have a conclusive evidence and you won't have panic attacks in the future.
Hypothetically if you did hav any brain injury, leading to hemorrhage, by now you wuld have developed symptoms such as sudden loss of consciousness, vomiting, seizures, e.t.c
In absence of such symptoms, it is unlikely there has been any damag to your brain. Still getting a MRI will be the best option in this scenario.
Do get back to me with the MRI report.
Regards.