personal essay

Ok, so it's a while before I apply to nursing school, but I literally worry about it every day. I really want to get into University of South Florida and they require an essay. If I retake chem (and get a B), with the forgiveness policy, my gpa will be around a 3.75. My prereqs will also be high. What worries me is explaining these bad grades. I got an F in chem and lab for dropping it after the drop ad period and I got a C+ in The Criminal Justice System. I also have a W in college algebra which I later received a B in (taking math in the summer is not a good idea). I had the criminology class in the morning and was also dating a drug addict at the time who was up with me at all hours of the night so I got 2 points off my final grade for attendance. For chem, I was falling asleep when I took the second to last test and literally didn't know any of the answers so in my half asleep stupor I forgot about the drop ad policy and decided to drop the class. I'm not looking for judgment. I am working on becoming more responsible and am actually going to an intensive life skills/ independence center for a year. I just don't know how to explain these grades to an admissions committee without seeming foolish or looking like I want to make excuses, especially excuses with poor reasons. I know I shouldn't use these reasons, but I also don't want to outright lie. These grades all did have one thing in common; they were all during summer semesters so maybe that could be part of the explanation.