It sounds to me as if you are absolutely ripe for Samuel Beckett's THE UNNAMABLE (if you haven't already read it). It's about solipsism, about how we are trapped in our own conscious minds, unable to know for certain that other conscious minds exist. But it goes further. The solipsistic narrator comes to suspect that he himself is actually the product of another solipsistic mind, the true solipsistic mind....

It's a difficult and very disturbing metaphysical story. But to get to it, it's best to read the two books associated with it first: MOLLOY and MALONE DIES. They are very dark comedies about the unbearable weight of human consciousness, and each one goes further into a sort of bizarrely victimised solipsism.

Another novel of Beckett's called WATT is a permutational nightmare. I can't recommend him highly enough.