I'm struggling in spite of "prioritizing one thing".

Like for eg: uni/studying.

I don't know how much is "enough" for the day(s). I feel like I "have" to do more, and that I could or "should" do "better", because I have spare mental energy/time.

To deal with the resulting discomfort, I then throw myself into more work, or try to argue myself into not doing more or to find clarity, which results only in overthinking cycles, wasting time and mental energy, and burnout.

It could be due to being indecisive. I don't know how to draw clarity in defining "enough" because any target or goal feels arbitrary and I usually have it in me to be able to push through and do more. I end up just working (or overthinking, usually overthinking) myself to exhaustion.

Ig I'm trying to be "perfect" - or, even if not, then being "maximally effective", and making sure everything I'm doing is "right" and gathered "right" too.

I cannot change my mode of action unless I feel safe in knowing that I am doing what is rationally "correct" or "right".