Probably the cyst released its fluid, and the release of pressure made you feel better. The nausea could be from the fluid floating around in your abdominal cavity after it released from the cyst. Probably it doesn't have a lot to do with the fibroid. I'd sure get that removed if you can.
I do not have an answer for you, but wanted to suggest that you give your gynecologist a call. I know that pain and nausea are symptoms of a cyst. Please let us know what you find out. Good luck and sorry I couldn't be more help.