It's very difficult not knowing the trigger, but never let that get you down. ;-) Its hard in the outside world but I never let it bother me, so niether should you Sirius. I agree with Callingforthesun;-)
I feel very similar about getting close to people...but it's more along the lines of how horrible my face looks and afraid of what people will think of me. ;-) But I know I don't have to worry about that, and I know there are always worse people than me-and I'm pretty bad- who I can be there for.:-)

But on a lighter note, welcome Sirius! I hope this site is of great use to you!;-)