My coworker had a similar problem last year around this time. He was having frequent nose bleeds and such and then finally it got to the point that he couldn't stop them. So he went into the hospital and found out they needed to caterize something in his nose. I forget what exactly it was but I'll ask. If you get to the point like him, where you cannot stop them and there's a ton of blood, GO IN! Don't wait!
Otherwise my guess would be seasonal allergies. Try getting a humidifier for your room - don't forget to turn it off when you leave
