I too started out with kidney involvment with my Lupus 10 years ago...they only diagnosed it 9 years ago though!!! I have found however, that with good doctors and wonderful support, that I could be in remission. I have many other problems that go along with yet are separate from my Lupus. The most important things right now are for you to find a brilliant nephrologist, and that you have support from your family and friends.
I understand your fear of a support group, and not even wanting to tell your friends...I was diagnosed when I was 19. It is difficult for friends and family to "see" what is wrong. But trust me...there are many ways to talk to them and "show" them how you feel.
I'm sure that things will look brighter for you. You have come to a wonderful, loving site!!! Hang in there!!!
"And in the end, it's not the years in your life that count. It's the life in your years."