Random bruises appearing?

i have noticed more bruises on my legs then normal ive always thought i bruised easily but out of the blue one day i noticed a huge bruise on the back of my leg along with a tiny one above it and i know i didnt run into anything to cause that, a couple days later i notice to mre bruises but on th front of my leg and now i have a new one but on the opposite leg. im a little concerned about this cuz ive never had so many bruises this fast at one time usually its one after another but now i have 5 and dont have a clue where they came from