Firstly, from a biblical standpoint a 'ghost' cannot exist. The concept of a ghost is that it is the soul of a dead human, trapped on the earth do to some 'unfinished business' on earth. Yet the bible say 'once to die, then to judgement'. So no, there is no 'ghost rape'.
Also, i notice you posted an occult based web site as your reference. If you're going on websites about things like this to begin with, that is probably the trouble you're having. You can't mix occult and Christianity. Psychics, tarot cards, magic crystals, communicating with the dead, mediums, astrology, ouija boards, astral projection, 'ghosts', horoscopes , and other similar things are all under the occult banner and strictly forbidden in the bible. All of that is based in interaction with demons. Period.
And if you aren't normally reading or involving yourself in these things, i still find it interesting that you went to an occult based site for answers. If there is some demon afflicting you in such a manner i'd say its time for some serious spiritual warfare.
I'd also say its time to really rethink your salvation, if its true or not. I normally try not to be one of those people i they are or are not saved. And i don't know for sure with you. But you say you're Christian, but yet also question God's very existence to such a degree that you put it in your name. Sure, we all have our moments of doubt, but something tells me you're going through more than a moment of doubt. Also seeking answers from worldly, occultic sources first, as opposed to bible, or other Christians even. And then if you're being regularly afflicted so strongly by a demonic presence, just something isn't adding up here.
First, i'd suggest going to talk to your pastor about whether you have been truly saved or not. Just as a precaution. Then seeing if perhaps he'd be willing to come and pray over your home, especially your bedroom, to remove any spirits there. And, of course, pray over you. Perhaps a few people could go to the house to pray over you and the house.
Finally, when these things do happen, dream or real, you should immediately begin calling on Jesus and his name for help. Just keep praying and calling on Jesus, don't stop. And stay away from those sites and that kind of stuff in general.