Hello @hopeimok - Welcome to Connect. Waking up to blood is kind of scary and especially in your situation. I had a similar bleeding situation that I noticed during the night but the bleeding was from my ankle area and had coagulated multiple times during the night and opened up again when I went to the bathroom which is when I noticed blood spurting out of my ankle.

You probably already found these possible causes but I thought it might help if not -- Bleeding from penis: Causes and when to see a doctor: https://www.medicalnewstoday.com/articles/bleeding-from-penis

Mine occurred because I rubbed my feet together and I had a untrimmed toenail that nicked a blood vessel near the skin surface. It's good that you are seeing a doctor tomorrow and I hope you are able to provide an update as to what was found. You mentioned no pain or injury. Did you see any area of bruising which could indicate blood beneath the skin?