i'm no doctor, but my current self help plan is to keep exercising cardio, low impact due to attributed anti-inflammatory effects, reduced carbs and sugar (i'm already low here but will probably fully go to zero). i've also started hyperbaric oxygen therapy which so far hasn't had immediate effects but does provide extremely deep sleeps which seem to help significantly.
I experienced this summer of 2020 on the California central coast. Symptoms lasted for about a month. Happened again around December 2020.
I had been on a high-carb low fat diet for a few months before the first incident. I think that may have made me more vulnerable to inflammation issues. I've since switched back to a higher (healthy) fat diet. Fat is protective for the brain.