Don't allow one bad experience to cripple your entire career or to permanently prejudice you against anyone who buys and sells art for a living. If things continue as they are, you'll become the classic case of the artist whose work gets the art world exposure and recognition it deserves only after he's dead. You're good enough and have enough of a track record that sooner or later a dealer will show your work. You're being your own worst enemy by refusing to let anyone represent you or show your work. The great majority of art dealers treat artists fairly, so don't let one bad experience impact how you sell your art for the rest of your life.
Dealers are an essential part of the art business.
They're the ones who know how to spread the word. As for your early successes, they're certainly significant, but not nearly enough to keep you going. Established collectors want to know what you've done lately as well as what you did twenty years ago. Newer collectors who like your work, but don't know you want proof that you're producing, showing, evolving, and continuing to attract the attention of the art community. You've got some rebuilding to do in this area.