You mention blood in you subject line but no more in the post.
Blood sounds a bit unusual, do you have a sensitive bleeding condition? I know some people get nose bleeds easily - and i think most can control them without medical attention.... I carry a packaged bleed stopper called NasalCease which I have never used. But, about two months ago I woke up with an uncontrollable nose bleed that sent me to the ER in the early hours of the morning. The ER doctor couldn't "fix" it so he installed a "Rhino Rocket", and nasal balloon that was removed a couple days later by my ENT doctor, first visit there.
My point is nose bleeds could be caused by the altitude change too if you have a sensitive nose, or it could be simply coincidental. In my case I was not flying (albeit I am a million miler on United AL) that caused the bleed, but could have been the dry winter air in my home.
As noted already, you didn't discuss the bleed issue, so I provide the above on that subject just-in--case my experience provides anything useful.
No, Just a bad reaction to the pressure fluctuation.