Lingering fatigue

How long can it take to recover from a single day of bad heat exhaustion? I’ve been to multiple doctors. Tests and blood work are good. I’ve been hydrating and resting, but have lingering fatigue almost a month out from my heat exhaustion episode. I am a very active person (10k+ steps, lifting, running), but have averaged 2k steps this month from testing which is driving me a little crazy. Even going to the store can feel overwhelming.