It's likely, even if it's only IgG that's elevated (in case this wasn’t a neutralizing antibody test).
One of my doctors told me that even if the virus is gone, the immune system could still be driving symptoms.

Supplements that may help if the virus is the cause:

Astragalus membranaceus is the most important one. 1 to 2 teaspoons of root powder per day. Astragalus extract capsules might be more convenient, but many brands are underdosed. Look for something like the NOW 500mg Astragalus Extract standardized to 70%. Avoid very cheap brands.

NAC gave me a minor benefit.

Green tea or EGCG extract might also help a bit—just don’t take it on an empty stomach.

Lastly, I avoid sugar as much as possible and try not to overdo it with coffee.

I don’t want to give false hope. This may not work for you—but it’s worth trying for a few weeks.

I dealt with symptoms for a decade—every 2 months I'd relapse hard for a week. It’s been over two years now with zero fainting or syncope. Every time I tried stopping astragalus, my symptoms and blood tests worsened.

I really hope this works for you—but keep expectations realistic— even though it helped me, it might not work for you.

Feel free to ask if you have more questions.