I'm sorry this happened to you. I have CRPS in my knees too and it was SO frustrating to not be able to walk. I hope they gave you crutches or some other assistive device for the time being. Sounds also like your doctors may not be the most expert at caring for CRPS. Neither were mine. Here's what I found out that I wish my doctors had told me at the beginning:

DO NOT ICE. On some level my intuition always knew this but I ignored it to listen to my doctors telling me to ice. That was a mistake and made me feel worse.
Move it around in the ways that you can. I know moving is probably scary right now, and kinesphobia (being scared of movement) is really common with this. Unfortunately, the only thing that hurts more than moving is not moving. Like littlepaw said, the pool is a really super helpful way to work out stiffness. The first time I did the pool I just held the wall and took the world's slowest steps in the water for about 30 minutes. It was amazing how much my limp reduced after I did.
I personally have found that kinesiology tape has significantly reduced my pain, swelling, and stiffness. There isn't research on this yet, but anecdotally from myself and a few others it seems to work.
ASK FOR HELP. This was really hard for me at the beginning, but I've found it's a brave thing to do. Let others help you with tasks and ease your stress.
Reduce your stress where you can. I personally sniff lavender and watch movies. Do what works for you!