There's Blood In My Post Nasal Drip. Prior To This,

There's blood in my post nasal drip. Prior to this, I travelled by plane and while the plane was descending my fore head felt like bursting with pain. I felt like thre were nerves that snapped. I consulted a doctor and we saw dark blood dripping at the back of my throat. I took sinupret for 1 week and do nasal flushing. After I week, I continued to have post nasal drip with streaks of blood. What shall I do?