Autistic Exhaustion or Something Else?

I feel exhausted after work. OK, many people, ND and NT do. It often feels like autistic exhaustion and I can't do anything else that day and sometimes not the next either (I work two days a week). But over the last few months (I'm not sure when exactly), "exhausted" has become light-headed, dizzy, faint and generally unwell, although articulating more precise symptoms than "unwell" is hard. Sometimes it persists into the next day.

Has anyone else experienced autistic exhaustion like this?

Unfortunately, there are a lot of other potential suspects to eliminate:

- dehydration (but it doesn't always go after drinking).

- low blood sugar (but it doesn't always go after eating).

- low blood pressure (I do have low blood pressure, but this doesn't seem like a normal 'standing up too fast' headrush and lasts a long time).

- medication side-effects (entirely possible, but I haven't changed meds for a while, so it seems strange that it would just start).

- sleep issues (I'm being investigated for a sleep disorder, so it could be tiredness related to that, although sometimes it persists after sleeping).

Thanks for helping!