I'm so very sorry for the loss of your little one
There should be a health guarantee on your pup and the store should refund you or give you a new pup when you're ready. I know you don't want to think about that right now, but you only have a limited amount of time to approach the store about this, so maybe your boyfriend can deal with the details for you.
I'm so heartbroken for you, and what a lovely girl she was too
