Dyscalculia

I am in my 20s and I think I have dyscalculia. In school I aced every subject all the time but constantly scraped a pass or failed lower stream math. I struggled with math all my life and it caused me a great deal of stress in my finals. It was always brushed off as not being my subject, but now I think I have undiagnosed dyscalculia.

I count using my fingers, it takes a long time to count usually I use my calculator, basic arithmetic causes me to panic, I struggle to work out how many minutes in x amount of hours, I struggle with parallel parking. A simple hour/ minute form to fill out could take me nearly an hour.

The thing is, sometimes at work I make mathematical mistakes and I feel like an idiot, if I was diagnosed would it even make a difference in that respect?

Where would I go to get a diagnosis?