Blood in bed, no injury noted

One morning last year I woke up and rolled over into a small puddle of blood. It was still wet, so I sat up confused trying to find the source of the blood. I check my body and found no wound that would indicate I was injured which further added to the mystery. I hadn't had a nosebleed, so I was very confused by the origin or cause. Even to this day I cannot explain where it came from but waking up to strange marks, being taken or Nhi being in my room at night is something not uncommon in my life, so I mentally added it to the list of unknown and without explanation.