I'm not sure you fit the profile for dyscalculia:
www.bdadyslexia.org.uk/dyslexic/dyscalculia
I don't know if it fits me but I get where you are coming from. Even at school I got brain freeze with the simplest calculations and number facts even though I breezed through English, French and German with A grades. My problem is not memory, it seems, so I'm not sure if it's some kind of deep-rooted fear! I hate things like train timetables, for example! Oddly, I was great at both maths and langueage at primary school. I'm not sure why it went tits-up at secondary level. 