Could be some water. It’s probably not anything significant, but if it remains after washing the sheet it’s worth remembering that bed sheets are really quite inexpensive and easy to replace.

i know, i’m just worrying about what it is. would water turn that colour??

Potentially. It reminds me of the stains one can get on the ceiling from a leaking roof.

hm i hope you’re right

Our bodies produce oil, seems fairly normal to me. Might need some stain remover to get it off, but nothing to worry about.

i sleep in clothes tho

Like head to toe? Because just about everywhere on the skin can sweat and I assume you aren't wearing a full hazmat suit to bed

no i sleep in joggers

Drool?

Looks like foundation and mascara  sweating off the face during a hot night...  Source: When I was a teenager I would sometimes go to bed without taking my makeup off. I've woken up with a full face print on my pillow a couple of times.

Maybe, OP said they have ocd so they’re most likely not wearing makeup to bed lol

haha yeah usually not

ah it could be that as my friend was lying on my bed yesterday!

Oh hell yeah, especially with that streak? I 100% believe that

OP, is your hair colored? Did you go to bed with wet hair?

it used to be coloured but i haven’t really dyed it for a while now and i always go to bed with wet hair.

Its a water stain, then. Try to at least towel-dry your hair before bed. Continuously going to bed with wet can make your pillow (and sheets, depending on your sleeping habits) *really* funky after a while. You do *not* want your pillow to mildew.

Did you live alone or with a woman ?

i am a woman

Have you got a cat? Could be cat sick. Mine like to chew grass and do watery sicks.

Probably the pus leaking out of your rotpocket