Why are you taking so many classes during the summer? That looks like quite a bit of work when put together and I would bet it will be pretty rough to do well at all these classes/jobs at the same time. My advice would be to cut a course or two if they aren't necessary to make sure that you do well. Also, it is the summer, you need to be "regenerating your work ethic" for the upcoming fall semester, at least, that is what I do. Me personally, I would take 2 classes and kick butt at the jobs rather than do too much and do just okay in all of them. My $0.02.
