It almost sounds like you are describing night terrors, where you see the actual room around you but also see the nightmare, usually a scary creature of some sort. But the shaking does not go with this, as night terrors render one unable to move until considerable effort is applied. Once you can move, you can fully awaken and the dream aspect disappears. Have you by any chance been on any tricyclic antidepressants or been in withdrawal from same. I have found that both on and coming off tricyclics can cause the hallucinations you describe, and, of course, panic is immediate! Best of luck in investigating the problem - billie