FedEx right now requires college and highschool transcripts, most airlines don't.\
Most guard units are pretty understanding as long as you show that you were working full time at the same time. Right now, holding a 3.0 GPA and working as much as you say you are, they'll probably look well upon that, since it shows you can balance school and work.
Not everyone gets the balance right on the first try, I certainly didn't.