I posted something similar recently. "The feeling of sneaking around" was my post subject line, I think, or something like it.
All I got was support. Wise and supportive words which I can now pay forward to you....
The truth is, if the shoe was on the other foot, they would not think twice about dumping you without any notice.
Your guilt is a good sign -- a sign that you are a caring person. Sociopaths feel no guilt when they dump people, but those of us with a conscience feel GUILT. However, this is not a healthy workplace and it seems to me that if you pull a sickie day in order to preserve your peace of mind in these dysfunctional times at this dysfunctional place, well, that's the Karma they have sown.
And just so you know, guilt is one symptom of change being made -- you are leaving the "old you" behind and entering new territory and it is a symptom of growth and change!