Entity in my bedroom - something touched me, still shaken

I'm hesitant to post this because it sounds completely unhinged, but I genuinely need to talk to someone who might understand. This happened three weeks ago and I'm still quite rattled.

I woke up around 2:30am in my bedroom in my flat in South London. There was this... presence. I can't explain it better than that. The air felt different, heavier somehow. I wasn't paralyzed or anything, just absolutely conscious of something being there. And then I felt something cold on my shoulder - not pressure exactly, more like a cold hand or touch. Just for a second. I actually screamed and turned on the light, and of course there was nothing there. Doors locked, window closed, no sign of anyone.

I've always been skeptical of paranormal stuff, which is why this has unsettled me so much. It felt completely real. Not a dream, not a hallucination. And I've never experienced anything like it before. I haven't slept properly since. I'm keeping lights on at night, which is ridiculous for a 34-year-old, but I genuinely don't want to be in the dark.

Has anyone had a similar experience? Any thoughts on what it could be?

Sleep paralysis can actually manifest as feeling a presence and physical sensations without the paralysis being complete. Worth looking into that first. It's genuinely horrible and completely explicable by neurology. Your brain's wake-sleep cycle misfires, you're conscious but your motor control is offline, and you interpret the sensations as external threats. The cold feeling, the presence, all of it fits.

That said, sleep paralysis doesn't usually wake you in the way you're describing. You're normally aware you can't move. The fact that you could move, turned on the light, nothing there - that's different. Could still be a waking dream or hypnagogic experience, but the geography of the experience suggests something else. Have you had other experiences since, or just the one?

I've always been skeptical of paranormal stuff, which is why this has unsettled me so much.

This is actually telling. Skeptics who experience something weird take it seriously because they know they'd normally dismiss it. You've got no confirmation bias pushing you toward belief. Have you considered talking to a GP? Not because you're mad, but because sleep disruption and anxiety about sleep can cause weird perceptual stuff. Medical route first, paranormal route second. That's just being sensible.

The South London area has had some reported hauntings in certain postcodes. Not to freak you out further, but if this becomes a pattern, it might be worth looking into the building's history. That said, the single-incident thing and the touching sensation really does point more toward sleep neurology than a genuine entity. Get yourself checked out, get better sleep, see if it happens again. Pattern is key.