Bruising for no reason?

I've discovered about 10 bruises on my body in the past week or so, that I didn't get from any physical injury or impact, and more just keep cropping up. I've also been feeling feverish and tired a lot lately (plus I've just gotten over a really bad respiratory infection). It's really gross; it looks terrible when I want to expose my arms or legs. What could be causing this? Is there a vitamin that can help?