New puppy blues or worse?

Im absolutely horrified that im writing this. I've just brought home an 8 almost 9 week puppy. I've been thinking about getting a puppy for years and I that time did so much research. I finally got my own place and over the last 2 months have been researching more and more and looking for one. I do have some health issues but i was in a good place with them and they were almost non existent. And I am very isolated and alone and thought a dog would make great companionship plus would get me out more, plus I fully intended on training so I could meet new people and for the dog to socialise as well.

2 weeks ago I found the most beautiful little chihuahua/ Yorkshire terrier cross. I've been around yorkies a lot before and a family friend has a chihuahua so I felt this was a good match. I went to see the litter and was expecting to pick up one of the males but this little girl won my heart over and I knew. Went back to see her a couple of times and on Sunday committed to getting her.

Almost instantly, id say within the first 3 hours, I regret it. Over the last few days ive been working on potty training and crate training. And while there is progress, it is minimal.

I cant say exactly what it is im regretting. Shes fine. I literally love her and im never mad at her for doing anything wrong. Shes a baby and I understand that. I dont even find her that difficult or hard work. Its not her. Its me. I am panicking at the thought of even having a dog any more. Even though its something ive pictured for years. Im hugely embarrassed that I thought i could manage this and bow I just want rid of her. Ive cried solidly for the last 3 days and im at my wits end.

I talked to my friend who was the one who kind of gave me the final nudge to go ahead and she said she had puppy blues with her dog the first month and her sister also the first 3 months. I dont think ill make it to the end of the week. I read so many things and I dont feel like this is normal. I feel like ive made a decision that I was so confident but still been wrong. I havent eaten anythibg in over 48 hours cause im sick with worry and I cant shower or use the rest room or even sleep.

What I want to know, is this normal puppy blues or am I correct in thinking, ive made a mistake. Please help because im heartbroken and embarrassed.