Don't sweat it. If you take it seriously (am I contradicting myself? oh well), you should do OK, even if you suck at math. These aren't high level math classes, so unless your prof totally sucks, you won't be expected to perform at an incredibly high level. Just do the following:
1. Don't miss any classes.
2. Write down everything in as much detail as possible.
This is the simple truth. If you suck, you'll need to work hard to get better. Don't be lulled into doing jack shit by your friends who are great at math. 1. They might be doing more work than they're letting on 2. They might just be better at it than you 3. They might have a stronger foundation to work from. This is about you, not them, so forget about how many questions they do and how well they do on tests.
3. Do as many questions as possible (practice, practice, practice).
4. Ask prof/TA for help whenever possible.
5. Ask friends who've taken these classes/are in math-heavy majors for help.
6. Don't beat yourself up if your marks aren't up to your standard. Just keep at it.
7. Hurray! Success.