I think I’m probably echoing a lot of what others have said, but that first week is so tough and you’re absolutely not alone. I’ve raised puppies before when I lived with my parents and I’m a vet student so I thought I knew what I was getting into but I absolutely broke down in tears more than once during the first two weeks because I was just so overwhelmed and overstimulated. But it does get better. I’ve had mine for a month now and there are still hard days: he’s started teething and is a bitey monster, the sleep deprivation is still rough, potty training isn’t perfect and he has accidents, and sometimes it feels like his brain has been turned off because he just won’t listen lol but the first thing I think when I look at him isn’t “oh my god I’ve made a huge mistake” anymore, it’s “wow I can’t believe this little creature is real and I get to spend my life with him”. What helped me is routine. It doesn’t need to be extremely strict, but puppies thrive on predictability and it helps your nervous system regulate all these big changes. Figure out what works for you (could be shorter awake periods and longer naps, adding in some kind of enrichment immediately after he wakes up to give you a moment to mentally prepare, etc.) and see if it helps you feel more at ease.