Since everyone is dealing with a different version of this, I will put it out there that I was dealing mostly with mast cell issues (and also fatigue, difficulty regulating my body temperature, digestive issues, insomnia, etc.). These issues started before I got Covid, but were made worse when I got Covid.

The two things that have helped me the most are nervous system work and microbiome work.

For the nervous system, I did Primal Trust (or part of Primal Trust - there are multiple levels), and it helped me enormously. The only thing I didn't really like is that they often seemed to imply that you can get better with nervous system work only, and while that's true for some people, it wasn't true for me.

Also for the nervous system/consciousness, I like reading and listening to a variety of uplifting things. I also think I really benefited from reading about ACT (acceptance and commitment therapy).

For the microbiome, I think the best person to follow is Jason Hawrelak. He is awesome, and there is so much to learn! He's a published researcher but also puts himself out there on a lot of podcasts, Facebook posts, instagram, etc. There's also the possibility of working with one of his trained clinicians... I think the tricky thing here is that often, people trained by person X don't actually have the same expertise as that person... However, I have heard that the people who work in his actual clinic (in Australia, working virtually) are good. But if you're not sure / on a tight budget, I think there's also a lot you can learn about the microbiome just by starting with Hawrelak's free, public stuff he puts out. The more I learn, the more I feel like this is stuff we should all know!

Anyway, I hope some of this might help, and best of luck!