I vote give your body a break - at least don't do anything crazy until you can get up without feeling dizzy! Right now, your body is fighting off the flu germs, so exercising really hard is only going to take away the valuable resources it needs to do that.
When you're feeling a bit more like yourself, start small - maybe with some walking or gentle bicycling/elliptical/whatever else you do. If you still feel alright, start to pick up the intensity. Just remember that it may take a little time for your body to heal completely and to get back to where you were. Don't be discouraged - you'll get it back eventually!
Feel better