I bruise really easily; is this a sign that something else is seriously wrong?

I'm a 20 year old female. I have at least six bruises on my body right now and I'm not currently playing any contact sport (I only run like twice a week), I'm not really clumsy, and they're not from anyone else. Most of the time I only notice the bruises after they've formed and I lean up against something, or I accidentally touch it. I noticed it awhile ago; maybe about six months since I noticed my multitude of bruises. This hasn't ever been an issue. I'm worried this might be an indicator of something else, something serious. Can anyone help me find out what this could be caused by? Thanks.