My little girls first heat lasted a little longer than that and her second heat was about the same. Have you asked your vet about spaying her and what does she weigh? Most vets around here like to wait until they are at least three pounds, my mom had to wait until her yorkie was 10 months old before she hit that mark and now at two years is a little overweight for her size at three and three quarters pounds. It is very scary to hand over such a little baby for big surgery!!! I hope all goes well and just take comfort in knowing a heat won't last forever!