My Chrome Browser font is very hard to read?

On some websites, like Facebook, Twitter, and even THIS website, the font is set to something that is VERY hard to read, no matter how close I zoom in. I need to highlight anything I need to read because it's that bad. It feels like it's a Helvetica Ultra Light font, but I've NEVER set my font to that on Chrome. In fact, I've never even messed with any of my Chrome settings. It's as if one day it decided to change the default font all on it's own. I'm getting very sick of it because it's making things very difficult for me to read. If anyone can help me with this issue, I'd highly appreciate it. Thank you

PS- Here is a screenshot of what it looks like. As you can tell, it's almost impossible to tell what anything says. http://i.imgur.com/V7xVw9S.png