Water retention Issues?

I am a 43 year old women with a hx of high blood presure,and asmtha which are both control with meds. On about appx. one year i have been on the Jenny Craig plan and i have lost appx 25 pound, however for the p 5 months i have gain appx 6 pounds. To increase my weight lose factors i work out between 3-6 days a week for appx 2-3 hrs. My main concern is the water retention that has occured 2 weeks ago that i have yet to release. I gain 4 pounds in one week. (ie) i work out hard and i weight my self and i will loose 2 pounds and the next day gain 3 pound back. I know it is water retention because i have effect eating plan in place through (jenny Craig) My question is what can i do or what can i put in place to decrease the on going issue of my water retention problem