12-week old regressed HARD in crate

We have a 12 week old mutt and have had him for about a month.

I am a student, but I don’t have many classes. My wife is a nurse. As a result, there’s about 1.5-2.5 hours, in no more than 90 minutes consecutively, every day where he’s going to be alone while I am at class.

His first two weeks were tough, but he has been very good lately In his crate. He would whine for a minute when we left, but would settle down. If we were at home, we did a “90 minutes on, 90 minutes off” system of enforcing naps where he would whine for a second before settling. He still did poorly in his playpen (literally throwing himself against the bars) but loved his crate, taking treats and toys into it.

However, since about last Thursday, he has regressed hard. Usually, I can do homework in the 90 minutes he’s asleep and then playing and give him attention during the other 90 minutes. However, since Thursday, he acts like he is being tortured when he goes in the crate. Today, he barked for 20 minutes straight. Not “whines and then a few minutes pass and he whines again” I’m talking 20 minutes of just straight barking.

I’m about to start finals, and I cannot go back to the time when, if I was home, it was a wash on homework because he needs constant attention or absolutely loses it.

I’m genuinely at my wits end.