Calm down, if she is in heat she will be okay, Lexie went into heat we thought about 6 months old, she enlarged but I never seen any blood, well she is 9 months old now and in heat, I saw the blood about 2 weeks ago and she is finally going out of heat...I would wait till she came out of heat to have her spayed. I maybe wrong and I am sure someone on here will let you know(not meaning that to be a smart...but in a good way) Just make sure she isn't around any male dogs for 3 weeks..she will be fine...
