I think you need to maintain full-time status for the loans.
You have 80% of my sympathies... It was 100% until I remembered that full-time means anything 12 or over.
I've always considered full-time to mean 18 credit hours.
You pay the same amount of money, regardless of it being 12, 13, 14, 15, 16, 17, or 18 credit hours...
Suggestion for the future: add in more "easy" courses simply so you get more exposure. Take those courses pass/fail, if that's an option. Then, if what's happening to you now happens again, you can easily drop one of the courses and still maintain full-time status. Or, as I did the first time around (when engineering students were allowed 20 credit hours), I signed up for 20, expecting to drop the course that looked like the biggest mistake.
But, for what it's worth, I did 18-19 credit hours, worked full time, and coached soccer for 3 years... hence only 80% of my sympathies.
(and majored in math - certainly not a cake walk)