It seems like the core issue here is that even though in a certain sense it would be good if any time you were sitting not doing anything, you were instead going off to improve the world in some way, in practice, endeavouring to do this would not be possible and/or would be counterproductive. For one thing, you need rest, so if you were to always (or just too often) try to do something productive rather than sitting around, you’d eventually fail/become less productive overall. More generally, it seems like, in the long run, you may well do more good by focusing on the highest important things (e.g. college work and your long-term career), rather than spending all available time now on direct impact.
Even more generally, it seems like the approach of worrying about whether, at each specific moment, you could be doing a higher priority thing, is stressing you out to a clearly counter-productive extent (i.e. you explicitly note that worrying about this is making you less likely to do anything productive). If so the best thing to do from a utilitarian perspective is not to try to calculate what the best thing to do in each given moment is and try to do it, but to take a more meta- approach of working out what kind of strategy will work to maximise the utility you produce in the long-run (see discussion of two-level utilitarianism). People face analogous issues in the context of deciding how to spend money rather than time: many aiming for a high level of frugality find that trying to work out for every small purchase whether it’s utility-maximising (even allowing considerations like “If I don’t buy myself an ice cream on this occasion, I will go mad with unhappiness in the long run, so I will buy the ice cream”) is too stressful for them to maintain in the long run, so they establish a more fixed rule that they will donate X, and everything left over they can just spend however they like.
It seems like the core issue here is that even though in a certain sense it would be good if any time you were sitting not doing anything, you were instead going off to improve the world in some way, in practice, endeavouring to do this would not be possible and/or would be counterproductive. For one thing, you need rest, so if you were to always (or just too often) try to do something productive rather than sitting around, you’d eventually fail/become less productive overall. More generally, it seems like, in the long run, you may well do more good by focusing on the highest important things (e.g. college work and your long-term career), rather than spending all available time now on direct impact.
Even more generally, it seems like the approach of worrying about whether, at each specific moment, you could be doing a higher priority thing, is stressing you out to a clearly counter-productive extent (i.e. you explicitly note that worrying about this is making you less likely to do anything productive). If so the best thing to do from a utilitarian perspective is not to try to calculate what the best thing to do in each given moment is and try to do it, but to take a more meta- approach of working out what kind of strategy will work to maximise the utility you produce in the long-run (see discussion of two-level utilitarianism). People face analogous issues in the context of deciding how to spend money rather than time: many aiming for a high level of frugality find that trying to work out for every small purchase whether it’s utility-maximising (even allowing considerations like “If I don’t buy myself an ice cream on this occasion, I will go mad with unhappiness in the long run, so I will buy the ice cream”) is too stressful for them to maintain in the long run, so they establish a more fixed rule that they will donate X, and everything left over they can just spend however they like.