Well, first of all, calm down. Everything is perfectly normal.
Don't freak out or you'll just upset her...
There's nothing to worry about. It sounds like you've covered your bases. Just keep a diaper or pad on her (which is really more for you than for her), and (like you're doing) keep her comfy. She'll probably eat a little more too...so make sure you add a little extra to the bowl...
As far as the spay...she'll do fine! They can do it if she's in heat...doesn't matter. The vet will tell you everything you need to do post-surgery...so don't worry about that either. And if you have anymore questions when the time comes...there are some very helpful folks on here who can assist with questions! Hope that helps!!
