Severe puppy blues or genuine mistake?

HI everyone,

I am fairly new to reddit and have mainly only used it to look up advice or training for my new puppy. I want to preface this post with the fact that I have had a dog before (he is 9 now) so I have raised a puppy before. I was on a waitlist for a mini dachshund puppy since September and was told I probably wouldnt get an available puppy until August. However, this specific breeder (very ethical might I add) had an accidental litter and was unable to advertise said puppies as it would not be good for her reputation, therefore I was offered one and picked her up last week.

I had done all the preparation for months, I had thoroughly researched all breed specific training and spent a lot of money on specific enrichment toys, crate, special carry bag for their spine etc. I was so ecstatic. However, once I picked her up I had this massive sense of dread and fear at what I had done. I have cried every single day since I got her, I keep thinking it was a mistake and that I desperately want to return her. I feel trapped and so flat and numb. Now, I know this sounds dramatic but I genuinely cannot make sense of these emotions and they have not gone away even slightly. She isn't even a 'bad' puppy, just a regular puppy and she is cute and its fun to play with her and she likes to cuddle which makes the whole situation worse.

Now just to add some context, I am 23 (f) and recently moved to central europe from the UK (August) and have struggled for months. The country was so difficult to integrate into, I struggle hugely with the language, the people are cold, I had to navigate the housing market alone and organise my visas as well as applying and reapplying for the visas for my partner to join me. I also struggled a lot with my new job too and as of around a month ago I finally felt settled and happy with the job and settling into the city. My parents dont think this is really about the dog at all and more that I have struggled for so long and finally felt okay again and now I have 'trapped' myself with another responsibility when I shouldn't have.

I did reach out to the breeder to try and express my struggles but she has not been understanding at all and it has mainly been more of a guilt trip. Now I know I am cruel and I deserve to be guilt tripped and I promise there is nothing I could hear that is harsher than what I have been saying to myself. But I just wanted to ask for some advice on whether this truly was a mistake because I dont really think I can trust my own judgement anymore. I just want to do what is best for the puppy because like I said, this breeder is desirable and I have no doubt a new family would be found soon and I'd rather she goes to someone who can give her what she deserves incase I can't pull it together as I would hate to evetually resent her when she didn't do anything wrong.

I appreciate any advice or insight anyone can offer.