First, I am glad that you are fundamentally alright.

Second, your symptoms are pretty consistent with a concussion - it's common to not remember anything from the event, and even from a significant period before and after the event.

Third, I appreciate your reminder about helmets. I try to not get too casual, and even put on a helmet to take a spin around the block.

Follow medical advice, heal up, and get back on the bike! Oh, but buy a new helmet first.