GPA tanked this semester. How bad is it?

I'm a freshman (well, sophomore now) at a weak-ish semi-target. I'm majoring in econ and plan on pursuing a career in IB, either straight out of undergrad or after getting an MFin/MSF from a target in the near future. Unfortunately, my cumulative GPA dropped from a ~3.9 to a ~3.5 this semester. I got a C in Introductory Microeconomics and a B- in Calc for not reading an email, for Christ's sake. I also had to withdraw from a course. While I have a whole host of excuses as to why this has happened, there really is no explaining these grades away. What I'm asking is if I still have a shot. I'm hellbent on making a 4.0 next semester and so on, of course, but I'd really appreciate a realistic assessment of what my chances are.

P.S. I have a business development internship lined up for the summer, and I've been told it won't be canceled, so it's not all bad, I guess.