I just saw this - I use toenail clippers on my girls - cut in front of the curve and they shouldn't bleed.....
I took Chanel to a VET to have them done 2 years ago and he had her back there so long I had to go see what was happening - he cut one too short and it wouldn't stop bleeding....and this was the VET....so don't beat yourself up over this.
and my other suggestion is next time - VALIUM !!! Take one before you start and you won't feel a thing
just kidding - but that hardest part I think is keeping them still