Today when i was in the swim-pool and i inhalation the water and i felt pain in my head (strong); now i see some blood comes out with the nose liquid?

Nasal irritation: You don't say if it was chlorine or salt water but getting a good sniff up the nose of either is enough to cause enough inflammation to cause a bit of bleeding especially if you blew hard afterward. It is a normal response to that happening, so is the feeling in the head. You will be ok. It is nota hood feeling. Sorry it happened. Take care.