I would listen to your mind / body. You're still developing your "productivity endurance". It will build up over time. Learning now to listen to when you can an

I would listen to your mind / body. You're still developing your "productivity endurance". It will build up over time. Learning now to listen to when you can and can't be productive will help later in life when incidents reduce (hopefully temporarily) your capabilities. You're also getting to see the downside of trying to push through it. What you're going through is something I'm dealing with now -- one of the side effects of some health conditions is temporary (or permanent) changes in endurance. One of the difficulties I have faced is accepting the days when I'm less productive and moving on in the hopes the following day will be better.