15 month old sleeping??

So my 15 month old recently decided she no longer needs sleep. Since shes was about 6 weeks old she has slept all night. Now the past week or so she doesn't want to fall asleep, she sits in her crib and talks and laughs for over two hours before she falls asleep. Then after being out for a few hours she is up again! She used to sleep from 10pm-8am or longer and now its 12am-3am then 5am-8am. Did anyone elses little ones go through this stage?? I tried making naps shorter and even skipping naps to see if that helped but it didn't! HELP!