Feeling crappy...

Calculus is a bugger for sure. On the bright side ... you have your test back and can see what areas you need to focus on. Also don't be shy and make an appointment with the instructor to see if he/she can guide you in the right direction. I TA'd several classes during grad school and those students that actually took advantage of my office hours usually improved dramtically. And FYI, I think I got a B in calculus and that didn't stop me from going on to get a masters degree and now I'm back in school working on my PhD.