Is getting healthy making me sick?

This sounds like such a strange question but I'm left to wonder / question.  I started my weight loss and journey to better health with Dan McGrath in February 2009.  It was great.  Loosing weight & inches and feeling wonderful.  I was not sick a day in 2009.  It was spectacular.  I missed all the colds, flu's and everything else that went around.  Now 2010 rolls around and I feel like I've been nothing but sick.  UGH!  It's awful. 

Last night I woke up in the middle of the night with a sore throat and fever.  Burning up!  That's a whole other question - how do you go to bed feeling great and get sick in the middle of the night?!  Since the beginning of 2010, this is the third time I've had a sore throat.  The last two times rolled into bad, bad colds.  I'm so hoping this one doesn't go that way. 

I don't get it.  I eat healthy; healthier than I ever have in my life.  I exercise regularly, never did that before.  I get good rest, at least 8 hours / night.  My stress level is manageable, lower than prior years for sure.  So what gives?  Why do I keep getting sick?