I think if you can rearrange things, it is the kindest thing to do for her. However, if you can't you just muddle through and try to give her you undivided attention more at other times. I'm a sahm so I haven't had to face this myself. I know it must be heartbreaking for you, too. Please don't feel like you are spoiling her by changing your schedule to meet this need. It is a stage and it will pass and she won't be spoiled by you spending more time with her. I know that in my culture there is a belief that 'what doesn't kill 'em, makes 'em stronger'. All this talk about 'they have to learn to be without you' bull hockey.
Anyway, I did show dd in a gradual way that I may leave and come right back. Then, I stretched the time out gradually. I didn't sneak out. I always told her that I would be right back. This seemed to help. I stayed close by so that if she cried for longer than five minutes, I came back to get her.
DH, and Me plus baby girl (10/07)