I, too, am terrible at math. It was related to some learning disability, but I was never told exactly what it was. I'm reliant on a calculator.
As far as self-diagnosis goes... I would not recommend doing that. It is better and the diagnosis carries more weight if it is made by a professional.
Maybe. I honestly don't remember if I went to a doctor about it, but I don't think we did. We did look up information on it though and all the symptoms and [parasitic bomb] match up perfectly. There is no actual "medical" treatment, that I remember. Or rather, there is ONE, that involves something or other, but it's more trouble than it's worth, especially at this stage, when all i needed was to pass one math class and never have to touch the subject ever again.
Instead there's therapy for it. Essentially, therapy that basically trains your brain to work right. tries to make both sides of the brain cooperate when problem solving. Problem is the therapy is aimed at young kids, since that's really when you have to catch it and treat it with the therapy, while the brain is still soft.
It seemed to work for me though. It helped me get through that one math class I needed.