One day I discover that there are unknown marks on my bed sheet(in light green colour, floral pattern).
One is like an oil stain, not large, but it's like potato chips falling on a paper and make some transparent dots on it. One is a larger spot, with faint edge, very light yellow colour (it locates on a yellow flower print on my bed sheet).
I previously living in a relatively unsafe place, and I'm worried if a crime had happened to me when I'm sleeping. I'm worried if those are semen stains? I saw someone on the internet said when semen stain dried, they appear to be white and crusty, but what do they look like after rubbing (sleeping on it)? Would the crust come off and become a oil stain-like spot?
In my experience the type of stain semen makes varies depending on age - when I was young they were the crusty sort and later if spilt on fabric tended to act like starch: nowadays it is more like a white dye and takes some getting rid of...
I suspect you believe someone might have performed anal sex on you while you slept. Do you really sleep that deeply or perhaps you were drugged? OR perhaps someone has watched you sleep while masturbating OR has used your bed while you weren't there???
Perhaps the stains are the result of something more innocent or perhaps you have had a nocturnal emission or two?
Certainly without other evidence or the benefit of information from a forensics laboratory it is pointless speculating and you could drive yourself daft by dwelling on it unless you really believe you were raped while you slept - in which case you need to get checked out by a medic to regain your confidence and prevent you inadvertantly doing harm to others...