On wednesday my 6 month old kitten was supposed to be spayed. I dropped her off tuesday night and right after i got home, the vets office called and said that her surgery was cancelled because the vet had a family emergency, so i had to pick her up the next day. I have to call tomorrow (Thursday) to reschedule. However, she's in heat at the moment. I heard that it's bad to spay them while theyre in heat, so how long does the heat last? When will i know itll be absolutely safe to spay her?