My little one has picked this up as well. Although my situation is different.
My boyfriend and I work overnight. 11p-7am. I come home in the middle of the night around 2am to let her out. When we get home in the morning we eat, and play for almost 2 hours then we go to bed, she goes in her crate (think of it as if we left for work). I was setting my alarm for around noon to let her out to pee (think of it as coming home for lunch) and feed her and then back to bed until about 3:30. The first month home this went off wihtout a hitch. The last week? she is up every hour.
I have started putting her in the bed because lets face it, I have to sleep at some point. But this isnt a habit I want her to get into. I know I should just let her cry it out but it kills me. I dont know what to do.