nightmares about trauma I don't have

!!TW:>! S/A / SEXUALITY!<!! kind of vent-ish but I couldn't do both?

I posted this in r/nightmares and i think it'll fit well here since I am looking for advice on this. Btw, I do have diagnosed depression, anxiety, and autism.

I (ftm 15) have been having consistent nightmares (1-3 daily) about getting>!s/aed and graped!< (I don't know what the policy is on that word so I'm playing it safe to not get like reported or something). The thing is, I've never been assaulted in my life. I have 0 trauma around that topic at all (except unlimited internet access since I was 8, which did make me stumble upon things I shouldn't have seen) and don't think of "it" happening consensually or non consensually on a regular basis. But I've been waking up feeling like I physically have been assaulted even though the hands I feel on myself aren't even real. The dreams aren't usually completely about >!s/a !<though. The dreams themselves are usually mostly normal and then the... dream plot I guess progresses onto a point where I get >!s/aed!< by somebody (usually an older man that I don't know). And then the plot moves onto something else usually also of equal stress and then I wake up. My body feels the hands, feels the exhaustion, feels dirty, and will probably have a >!hypersexuality !<episode-- but none of it was real??? I don't know where this is coming from and why I feel so physically affected? I feel almost invalid feeling the responses of someone who has actually gone through that since my interactions were completely made up in my subconscious. what is going on? why is it so consistent over every night? Why am i feeling the effects physically even though the action was in my head? Why do I feel the hands of someone who doesn't exist and who never touched me?