Friend's new sofa

Crazy, when I was 21 (yes, 21!!) i was staying all night at my friend and her new boyfriend's apartment. They had just gotten a brand new sofa and invited me to sleep on it. That morning, early, before dawn, I woke up cramping and feeling something wet and when I turned on the light, I had started my period and a quarter-size drop of blood was on their new sofa!!!!!! I felt terrible. I got in the bathroom and got a wet washcloth and scrubbed it out, then turned the sofa cushion over so that the wet spot would not be visible. I could hear my friend's boyfriend mumble something, and then I heard my friend say, "I don't know what she's doing.." I did confess it to my girlfriend later. I felt horrible about the whole thing but there was no stain left.