Or there could be other possibilities such as if you are on estrogen replacement therapy. You are not taking any heart medications so heart trouble would be unlikely. Your best choices for diuretic herbs would probably be corn silk, watermelon fruit, and watermelon seed.
Juniper berries are a good diuretic as well and they strengthen the nervous system.
Though long term use can irritate the kidneys, so it should not be used for more than 4 days straight. It also lowers blood sugar so it is not advised if you are hypoglycemic. Uva ursi is sometimes recommended as a diuretic, though I would advise against this herb or any other high tannnin herbs since they can precipitate your medications from your body. You definitely do not want to do that with these medications. Potassium is also recommended sometimes for water retention, but again I would be cautious with this one.