I would definitely talk to your boss -- it is entirely possible that you are just doing these tasks for the summer while they are shorthanded, no? Maybe if you find out that these duties will end in September it will make you feel better about continuing. I know that I feel better when the end is in sight

Doing boring busy work like that is very frustrating when you want to do something more, but it could be a positive while you are trying to figure out the right combo with your doctor. It's not taking a lot of mental energy and you are familiar with it, even if it is emotionally taxing.