Have you tried different types of in person meditation classes? I've been to one before where I had to sit in the middle of a circle and they dangled crystals around me. I found that really uncomfortable from an SA point of view and I kept worrying that I was going to get whacked in the face with a rock. I couldn't relax.
But recently someone mentioned singing bowls and how some places use those as a sound to focus breathing on.
Sorry I'm not sure of apps, but the guided meditation cds that I've used in the past are good, so apps must be too
