horrible puppy momma

every time something happens to tatum i kick myself for days. i originally selected her breed because they are great running dogs and can run pretty far for their smaller size. so she's been running with me since she was about 12 weeks old. but she has always pulled back while i'm running. it drives me crazy. it's like resistance training with a 19 pound lead weight while trying to run. last night we set out to do 4 miles. she's gone 5 before so 4 is not too much for her. but she's been licking her paws lately so i've let her stay at home while i run. BUT she is also bursting with energy so i thought "ok, i've let her rest long enough, today i'll have her come with me." well on our way home, literally feet from our front door, i realized that her paw was bleeding and i wasn't sure which one. so i hurry inside and check her out...BOTH front paws were bleeding. but there were no cuts or scrapes, it's just like her pads were worn thin. oh just typing it makes me cringe. how could i make an 8 month old puppy run 4 miles? i've asked the vet, 2 vets actually, one was her puppy vet in florida, the other was her new vet here in colorado. and BOTH of them said as long as you increase the mileage gradually and she doesn't seem to mind it she can go as far as you want. so...we started with half mile jogs, moved up to a full mile. added another half mile. you see the direction i'm going? slowly slowly from 12 weeks to 7 months we worked up to 5 miles. ugh. i feel so bad. i think i'm only going to take her for walks from here on out. i can't stand how aweful i feel.