Don't even second guess your actions. You did the right thing. I remember when I had taken in a stray female cat who went into heat 2 days after I got her. But she seemed to continue being in heat. I brought her to the vet and upon x-rays, examinations, etc., they found a cyst on her ovary and that is why she was having, what they called a continuing heat. They said that they will spay her but there was a chance she would hemorrage. I had no choice but to go with the surgery. Fortunately she came out fine and I kept my sanity.
You can book another appointment with your vet when she comes out of her heat. I would have done the same thing. So good for you, for standing your ground and doing what was best for your Cali.