That same thing happened to me with Willow. It was last year, Labor day wk-end. She was going in the first of the week and on Sun. night she began to show. Then my Vet wouldn't spay for another 2 1/2 months because of the harmones and the different cycles of the heat that I didn't even know existed. Anyway it put it up to the first of Dec. and I didn't want a sore baby at Christmas so she was finally spayed in Jan. At least I didn't have your other concerns. My other is a female and they are never outside without a leash and me. Just keep repeating, "this too shall pass."
I feel for you but gosh! You have a new house, how exciting. Best of luck.