I have NEVER read anything about antibiotics being contraindicated after a concussion.

What kind of infection do you have? Some antibiotics hit harder than others.

I had to take a few courses of antibiotics this past year. Eye surgery, hand surgery, hernia surgery, and toe surgery. The warranty ran out and the parts started falling off.

As an anxious person, be prepared for intestinal upset from antibiotics. The gut has almost as many nerve fibers as the brain. The nauseous feeling from trauma or stress is those intestinal nerves getting stimulated. Changing the bacterial balance in your gut could be uncomfortable.