['I took this calculus test last semester and I did way worse than I thought I did which made me mad.', 'oh that sucks.. sorry about that. but you can always improve, dont worry', "Yeah that's true, but I just thought I did so well and I didn't at all."]
I can feel your emotion.. dont worry, it happens to the best of us at times.
One time I took a test in calculus and I thought I aced it. Contrary to this I actually bombed it which make me really angry.