Have you tried using the banishing ritual of the lesser pentagram? It's what the group did every time before channeling Ra. I've used it in the past to deal with psychic attacks and can attest to its effectiveness there, so it might help with what you're going through now.
A link to how to do it:
http://www.kheper.net/topics/Hermeticism/LBR.htm
A link to how to do it:
http://www.kheper.net/topics/Hermeticism/LBR.htm