[Maya] UV shell fragmented

Hello everyone,

I've been doing UV maps without problems until this particular one just fragmented parts of it and flew everywhere. I've frozen and deleted the history, deleted the UV and started again, used planar and normalize, tried to sew and it just refuses to work out. I'm a beginner at the program (in fact this is homework and I have a deadline for monday morning...) and googling it hasn't been much help, I'm completely lost. I'd appreciate if anyone here could point me in the right direction. Thank you very much in advance!