Sounds like you've got a good head on your shoulders. Mescaline, as advised above might be the way to go, although low dose of shrooms shouldn't be too difficult either. Work up slowly and NEVER be lulled into a false sense of security. Playing with your mind is about a thousand times more dangerous than fire...

Just to give you an idea:

a low dose of mushrooms is a tap on the finger;

a medium dose a handshake;

a high dose a rap on the knuckles;

any dose of spice is potentially a baseball bat to the face, and a high dose is a scythe across the neck that'll pull your head from its root.... (sounds like you've been here already)

welcome to the nexus, from a member your age whose panic attacks have always occured while deep in the spice trance.

JBArk