Definitely do NOT beat yourself up over this. I believe that faith in yourself is your greatest ally. Take Karen's suggestion/offer of help. And I know it sounds crazy, but keep telling yourself "I can do this". And you can do this!

I'm with Scooter's Mom.....I have to have a piece of paper to do simple math. I can balance a checkbook, but anything more is asking a lot. My SO does the algebra equations in his head - I'm always amazed when he does that, since he is dyslexic. He can't write the numbers down - they look all jumbled up, but he can do it all in his head.