It's normal to have a bloody nose every once in awhile. Some people get them all the time while pregnant. It's due to all of the extra blood circulating through your system.
When I was early in my pregnancy I would vommit so hard it'd cause my nose to start bleeding apart from my nose already bleeding every once in a while. I'm sure it's normal.
I'm 15weeks and by the time I was 12weeks I was having nose bleeds quite frequently despite never having them before then in my life!