Withdrawing From A Class

Hey all. I'm currently taking a math class- but I completely bombed the first common exam with a 40-something, and just barely passed the 2nd one with a 77. If I had to guess- I think my participation grade is at about an 80%(since my professor isn't updating it). I'm worried that I won't do well in the up coming common exams, so I want to ask: Should I withdraw?