Falling apart

Physically, not mentally. Although...

I'm pretty sure it's cluster headaches I've got, although it's not like I'm qualified to say for sure, but the diagnosis is made based on a time pattern which I know the headaches fit, so...yeah. And now I'm starting to think I have some problem with something, I don't know if it has something to do with metabolism or blood sugar or blood pressure or something else, but this morning I had to do a bit of running when I realized I'd dropped my gloves, had to run halfway back to my house and then all the way to the bus stop and ended up feeling really light-headed and a bit nauseous and could barely move/breathe. I ate breakfast, but being a small person, I don't eat that much (I get full really easily, I'm not anorexic). I rarely have any energy, and when I do it's not for long, and apparently I can't jog for a whole...30-60 seconds without wanting to collapse in an exhausted heap...