You've mentioned taking thyroid medication, yes? According to my pdoc and other doctors, both hypothyroidism and the medication to treat it can cause fatigue. Add antidepressants to the mix and...I don't know, but I'm always low energy. One or maybe two "things" a day is my limit, too.
What has your doctor said?
May those good things keep happening to you even if you cannot feel them the way you would like.
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My dog

mastered the "fetch" command. He would communicate he wanted something, and I would fetch it.