What Causes Flea Bite Like Blisters On Inner Calf That Bleed On Scratching?

Hi , I am three months pregnant , and I now have what would seem like flea bites more on the inner left calve of my leg but there is some on the right leg. I have just out of nowhere scratched my hip and it started to bleed. Also I noticed now that if I scratch my legs they bleed. I do have a cat, but there are 3 other people in this househould who don t have this problem at all and the cat very rarely goes outside. I think there going to scare. What are they ?? Samantha