Never feeling rested?

Title: Never feeling rested with POTS?
Does anyone else with POTS just never feel rested? I was diagnosed about 4 months ago after 2+ years of symptoms and lately I’m realising I can sleep 9+ hours and still wake up exhausted. The other thing that’s confusing me is that if I have a busy day, talk a lot, go out, use too much brain power, or even do too much physically, I sometimes feel almost flu-ish afterwards with a sore throat, achy joints, feeling heavy, and completely wiped out, and it can last into the next day or sometimes longer even though I don’t have a fever. I also have ADHD and autism so I know overstimulation can make me tired too, but this feels more like my whole body crashes after I’ve done too much. Is this something other people with POTS experience, and how do you manage the constant exhaustion and feeling so rough after overdoing things?