I've been there. I had one transition for 3 weeks part time... cryed at the door the entire time. She napped well... her only saving grace!

She then started full time and continued to cry at the door for another 3 weeks! UGH! I just about terminated and then she settled down. She's now ( a year later ) one of my favorites! Great sleeper, great eater and just loves me.

Hang in there... if you can handle it. But I think a more consistent schedule will help.