We've only had one time that looked anything like a breeding when the doe didn't kindle 30-32 days later. And often we were pretty sure when we saw them haystaching. When we were in doubt about a breeding we tried again later that day or the next day and if the doe growled and was really uncooperative, we understood her to be pregnant. I know this is not everyone's experience and you don't really know until thirty some days from the breeding. Some palpate at about 2 weeks, but even that doesn't always give accurate information.
Waiting is hard, but it's the only way I'm sure you can tell.