I'm 21 too and I am increasing my course hours and work hours along with doing some activist stuff and I get down about my two babies too, but you have it down to a schedule and I don't even have that so that's a plus
I wouldn't give him up unless your situation is making him unhappy or stressing him out. I believe they are more forgiving than we think they are. If it works with your schedule maybe you can visit him more often in the day or take him on little errands with you if possible. I just make the hike from work or classes in the middle of the day to visit them and say hi.
I didn't/don't necessarily crate train Hooks. I have an aversion to crates since my other pup spent his early life in one and can't stand them. It is like this large bin that he can't jump out of and it is open at the top so it doesn't give me the mental image of a crate while serving the same purpose
I hope that helps.