Severe puppy blues and nipping

Please help! 😩

Hi all, as the title says, I’ve been having some bad puppy blues and my little guy is biting at me and my partner.

hes a 10 week lab/collie mix who we adopted 2 weeks ago. He came home with us and 3 days later had reduced appetite, turned out to be parvo and he was hospitalized for two nights but survived (we hadn’t even had time for our insurance to kick in yet). Hes been so bitey with us, and it’s terrifying me as my sister adopted a pup who is 5years now and he has serious biting issues. I dont know what is “too much” for a standard puppy. He’ll start nipping and we’ll try freezing and saying “no” so he’ll eventually learn this word. When he’s jumping at us and biting, we’ll hold his collar still to first off save us, but to calm him down. He hates all things that involve not continuing to bite us and usually will just keep at it, so then comes the difficulty of time out. We’ve tried a leash in the door to refrain him from running around, he doesn’t get it and just pulls till his neck is sore, so I don’t like doing this as it hurts him. He goes in his crate well with bribes at night and doesn’t moan. He also doesn’t like going in his crate during the day, so we have used it for time-outs since his leash doesn’t seem to work, and he hates this scenario, so thinking we’ll just have to keep doing this. I don’t know what else to do to stop the nipping?!

to top it all off, I’ve had horrible puppy blues. I am just wracked with feelings of guilt every day, and feel so nauseated about it that I can no longer eat. I hate this so much.
I know it will get better, but just really looking for reassurance and helpful suggestions at this point. How long will this last? I want to be excited about him being with us but I just feel so upset all the time, and when he starts biting I just feel angry.
PLEASE HELP 😩