Good for you, bringing your "issues" here for help and support!
Being a nurse, I know nurses often do not ask for help when they need it; we see ourselves as the helpers, not those who need assistance. But, in truth, everyone can use a support system!
As a nurse, you probably have some understanding of the mind-body connection. In my practice, IBS responds very well to the stress-relief of progressive relaxation & guided imagery. You might want to find yourself a CD that would help you relax AND one that could help you drift off to sleep if you really want to change your sleeping habits.
Avoiding meals at work is not a good idea although, I understand why you would do that. I'd recommend you find a few things that really work for you -- no one but you can determine what foods those might be -- and keep them "at the ready" to take to work. Running on empty while trying to make decisions about others care can slow you down and get you into trouble.
As a single woman now, learning to take good care of yourself needs to be a top priority! I'll be pulling for you and hoping you identify some strategies that you can weave into your every-day life for health and wellness!