I understand where you are coming from. Sickness and medicine will unfortunately do that. It is discouraging, I know. Gotta just pick ourselves up and start again. If you had the strength and will power to begin the first time, then you know you have it in you to do it again. Right after my illness (17 days of bronchitis), my center suggested I try drinking 84 ounces of water a day to flush out all the medicine and retained fluids. The next week I dropped five pounds.
As for zumba, I really do enjoy doing it, although I feel like I look like Elaine from Seinfeld (hope you've seen that episode, but if not, just know it's BAD dancing). I just get in the back row and pray no one has their camera phone pointed at me! It's much more fun than running to me, but everyone is different. Regardless, just get back on program, up the water intake, and see if that helps.
Straightening up and flying right since 1/7/2013!