Suggest Treatment For Cracking Sound In Knees

Hello, I am 16 years old. A month ago I relised that my Knees were poping now and then when I would get up off the couch, chair, school desk, ect. This problem only got worse; now, my Knees are poping every time I get up. It's beggining to concern me, not to mention the way other students look at me as I get up to turn in a test in a dead silent class room. Any help would be much appreciated.