You have four freshmen playing significant time, with two of them starting. That's the biggest problem right there. They've also got poor stamina and you're running a fcp.
And the fact that you've got two guys starting and playing 15 mpg makes me think that you are subbing by target minutes rather than fatigue, which will make your team play all-around worse. (If I'm right you're obviously doing that so that you don't have to play the freshmen starters 20/25 mins, which I get, but you're still hurting your team overall.)
Also, with a very young team that's struggling (and also has weak rebounding), I think you should've been running slowdown.