I have Hashimotos and ADHD. Wanting to do all the things and not having the energy is so frustrating. Learning to accept where you are at is very important. Brain dump all your ideas, but don't hold on too tightly to them, cull your lists regularly so you are not holding yourself accountable for things you don't even want to do anymore just because you wanted to at some stage.
Diet and exercise are really important for me personally, eat regularly but (try) to keep it as healthy as you can. Try cutting out gluten and/or dairy, but keep in mind these are not compulsory, if you don't see improvement, eat what you want.
It's worth looking at adjusting your thyroid meds though if you don't have lots more energy than pre-meds. They can take months to become effective, but also you have to experiment a fair bit to find the right dosage. You should have a lot more energy on them.