I drank one cider about 8 months after my first concussion and had a migraine/nausea the next day. This was also a very anxious time for me as I was graduating college and having to deal with my divorced parents spend time with each other across the country in my presence.

Three months after that I could drink without any issues. After my second concussion I was able to drink just a month after recovery without any issues. Don't forget that alcohol can make you feel pretty terrible even when you don't have a concussion.

For what it's worth, in the rugby culture at my school, kids will get concussed during a game and not know it, drink heavily later that night, feel terrible for a few weeks/months, and end up recovering just fine in the long run.

I definitely don't recommend going through that, but I wouldn't be so anxious about alcohol destroying your chance of recovery. As everyone else recommends, avoid alcohol for now. Maybe try one beer once you've felt better for a few months and see.