I know exactly what you mean. I have not yet been diagnosed but most of the symptoms describe me, and yet, I am one of the "nicest people" that everyone knows. People assume that I am extremely innocent and loving and always come to me with their problems (which I pretend to feel bad for but most of the time I just want to tell them to suck it up because I can go about my day with unbearable moods and not say a thing). I'm the funny cute one with the "clown face" like you say. However, I find that I take comfort in my internalization. I'm too prideful to share my feelings and I don't trust anyone with them..whenever I feel that I have over shared I get these dirty feelings as if I have given a part of myself over to someone.
Anyway, hang in there. It was really nice for me to see this coming from someone else because I often feel that these days I am the only one who isn't constantly complaining about their "stress".