i understand how you feel, but going to tanning beds doesn't automatically guarantee you'll get melanoma.... i certainly would stay away from them from now on though!
i have a family history of melanoma, and i used to go to tanning beds all the time in my twenties. there just wasn't enough information out there, and i really just didn't know any better. now that i know, i take precautions as much as i can when i'm going to be out in the sun, and i especially try to guard my children from the sun (reasonably though, a little sun each day is healthy)! it's all i can do. it's all you can do as well. take precautions when you are going to be in the sun, pay attention to any changes in your skin, and live your life.