Sleep Issues

What happened to my good sleeper??? For the past 2-3 weeks, Gracie will go to bed easily but wake up between 2-3:00am and can't seem to go back to sleep. Once I get her back to sleep, she wakes up within 10 minutes. I am hoping it's just a phase (I've read that when babies hit milestones, it can disrupt their sleep... and she's hit quite a few lately.) Or maybe it's her teething. I'm not sure what it is but it's throwing us all for a loop! Let's hope things settle down soon!