The heat cycle lasts 3 weeks
My Jess was just in heat,and before Lady was spayed at 7 months old,she was in heat too.It gets VERY messy,especially if they like to lay on the bed,couch..etc.
I had to keep giving mine butt baths because the smell of blood wasnt very nice the whole time
After three weeks they stop bleeding,but they stay swollen (vulva,breasts) for another week or so.I hope Iv helped