OMG this lady sounds way too dramatic!
Of course your pup wont die, sounds like shes trying to scare you out of getting one.
I work full time 11-7 mon-fri and I have a young pup.
I live with my mam and dad and they too work full time but we all work different shifts so Poppy is never left alone for longer then 4 hours.
Just make sure you pop down in your lunch to check on the pup if you cant get someone to do it for you
I would recommend you keep the pup crated or in a safe pen when you are out so they cant wander around the house and get hurt (and go potty everywhere).
Dont worry good luck x