Feel really embarrassed after maths questions at an interview

Hi all, first post on here. I'm asking this to maybe receive some reassurance or get a bit of a reality check – either one is welcome really. Today I (M 22) had an interview for a Junior (Casual) Bookseller position at a bookstore I've been eyeing up for a while. For context, I have been never been good at maths and I failed the subject horribly in school. I've just however graduated from a Bachelor of Arts degree and now doing an Honours at university, so I think I'm smart in some areas and completely inept in others. Anyway, the interview was going pretty well until they threw three maths questions at me: "Basic" equations I had to quickly think in my head and say the first number that came to mind. One was a subtraction, the other a multiplication and the other a percentage question. I'm pretty sure I fumbled all three (they didn't say whatbthe right answers were even if I got one of them correct). I just completely froze up, and could not think to save my life. I left feeling honestly really embarrassed and that I probably didn't get the position. Is this a normal response when put under pressure? Hoping to get some insight. Thanks a lot.