I never know if I'm doing 'enough'.

I don't know if other people ever feel like this (or feel this as often and as much as me), but I really struggle to know when what I am doing is enough. How much effort should I put into things? How long and how hard should I work? How should I be spending my time? I've seen other autistic people discussing how they have taken the phrase 'do your best' too literally and I worry that I do the same, or the opposite - that I'm not doing nearly enough.

It doesn't help that this year I've been learning to accept that I simply don't have as much energy as my peers. I see everyone going out and doing all of this stuff and I just know that I could keep that kind of lifestyle up for about a week before feeling so drained I can't do anything for the next month. It's paralysing to watch everyone doing and being so much more than me. I want to do so much, but when it comes down to it, I feel so lost and afraid. I often joke with my friends that I wish I had a little assistant who could tell me what I need to be doing and when.

Getting motivation is difficult because even if I commit myself to doing something, my brain starts telling me all the other things I could be doing, and that perhaps I'm not using my time correctly. I don't know. I suppose I just want to know if this is common for other autistic adults, and how I could begin to navigate this. I'm 20 at the moment; is this something I'll simply 'grow' out of, or is this forever? Is it pointing to some ultimate feeling of purposeless that I won't be able to be rid of until I find said purpose?