Is She In Heat?

I have a cat with 7 week old kittens and is going to be spayed soon. I was wondering what the noticable signs of heat are? Also, is it possible for her to be in heat when she has only 7 week old kittens?

a cat going into to heat will become very friendly, meows (moans) alot, when you pet her, she'll sick her but in the air and maybe mover her tail to one side... Well that's what my cat does when she's in heat and she's going into the vet tomorrow for her spay.

Cats can come back into heat within days of giving birth