I've been struggling with these symptoms and similar alien abduction experiences which led me too this forum. Before I go any further and explain my experiences I think it is prudent to make clear that there is a definite scientific explanation, that of being locked in a dream state whilst being awake, which I agree with. The condition sleep paralysis can cause experiences that can feel very real and horrifying as I have found out for myself.
What tends to happen with me is that for whatever reason I awake in my sleep(yet not entirely awake), unable to move or cry out for help, completely paralysed. This can either happen with or without a 'paranormal' occurrence accompanying it. My worst experience involves being confronted by 3 humanoid beings standing at the foot of my bed, their heads oval shaped(the classic alien description). The fear is so real, more real and petrifying than any fear I've ever felt, but because I'm quite rational I fought the reality of this and managed to confront the vision and ward off the intruders... it's particularly difficult to explain how. I've also been dragged violently out of bed, hit over the head and have heard voices that are best described as evil or demonic accompanied by a sound that is like a ringing/frequency, again very difficult to describe.
Taking all this into account, it is easy to see why some people fervently believe they have been abducted by aliens. Again I must emphasise the fear and despair that could make this particularly convincing to some; it is utterly overpowering and unlike anything most people will ever confront. I'm 22 years old and it has left may afraid to go back to sleep knowing this dream state paralysis could come again. Despite this, an illusion appears to be the best explanation. Many alien abductees claim sexual acts being carried out on them; either being forced to have sex or experimented on. I can tell you that sometimes during sleep paralysis I feel a rush of blood to the genitalia and this sense is confirmed by scientific studies which explains why your dream state will create a scenario for it(not dissimilar to teenage wet dreams). There is never any evidence of anything occurring out of the ordinary from an onlooker so that rules out any alien visitors(from this dimension anyway). There are never any physical affects noted other than those which could be caused by the person themselves. There appears to be nothing to suggest that it is anything more than a dream.
The problem lies in that it is more romantic to accept the wonderful thought of something supernatural happening(there's a part of me that wishes it was) than it is to put in the rather dry scientific research to find out the trivial rational explanation to what is going on. Maybe this post will help you, Joshua, in understanding just what is going on.