Accidentally Lightening Period?

Hannah • Certified Nurse Aide, aiming to become a dentist. Warning: democratic views on most things.
  Has anyone else experienced this? My period is usually very heavy and lots of cramping. To make it worse, it lasts an entire week! Well, maybe a few days before it started, I began drinking more water and exercising. I also began eating more fruit, not necessarily eating healthy, but fruit is in at least two of my meals every day. 
 Now, when my period started, I just thought it was spotting because it was so light! But it didn't stop, and it started when my period was supposed to, so I can only assume it's my period. Day two, it was still super light. I wasn't having the massive cramps that I usually have. Needless to say, I was pretty confused (and still am).
 On day three, nothing's changed! It's still crazy light, and I'm having no cramps. Has anyone else had such a massive change from a little lifestyle switch? Should I expect my period to take longer since it's so much lighter?
PS I am very healthy, so I don't think it has anything to do with illness. I'm also not stressed (summer!), and I don't take any Ibuprofen or the like.