It's a pretty common thing at your babies age. It will settle down again, and then you'll be surprised by the next little spurt of night time waking. Both mine wake at night when teething, sick, cold, about to roll/crawl/walk/talk. Ds at 16 months is waking at least three times, and I think it's a word explosion about to happen (I've been awake since 4am with him trying to resettle, but then he woke dd at 5:30 and then they both wanted to get up...*yawn*)