How do people get through this? I still can’t leave my 4mo puppy alone

I have a four month samoyed puppy that my bf and I brought home at 9 weeks. he has puppy class once a week, does 2-3
30+ minute walks everyday, mental stimulation games, sniff walks, playing with toys. We've done crate training since the day we brought him home, and we're finally at a point where he seems to like being in there... only with the door open lol. He didn't sleep through the night until we started leaving the crate open with our bedroom door closed so he can move between the crate and the floor. We can leave him in the crate for maximum 45 minutes while he eats a frozen toppl, but as soon as he finishes it he goes right back to barking nonstop. We live in an apartment so we can't let him bark incessantly. I work in office 2 days a week and my bf has had to cancel therapy, appointments, etc on those days when he’s home alone with him. When I take meetings at home I have to ask my bf to watch him and keep him quiet. He is the best dog dad but i know he gets stressed/overwhelmed too. We don’t see our friends anymore, don’t go out anymore, don’t have sex anymore. It feels like its not going to get better and we’ll never have a life outside of him again. It’s been 3 straight months of watching him 24 hours a day. I’m just exhausted and starting to feel resentful and depressed. We love him so much but I keep missing our life before we got him and wonder if this was a huge mistake. Someone please just tell me it’s going to get better, the puppy blues are hitting hard this week!