Contact lenses are turning my eyes red?

So, I got contacts in November-ish. They've been fine until the last week or so. They turn my eyes a pinkish-red color, so all the time it looks like I have pink eye. Anybody know what might've happened, so I can avoid a dismissal from school and a trip to the doc (it wouldn't be good, since I'm far enough behind as it is since I was absent for three days last week..)? - Thanks!! :D