Having a fear and having it somewhat come true is hard. I really feel for you since I had that happen to me. If you are planning on going into work tomorrow and your boss will be there maybe you could go in a little early and talk to her. You may have scared her but it may also not have been the first time she has dealt with someone who started to "freak out" (for lack of a better term). She knew enough to direct you to go to the hospital and to get ahold of your mother. Talking to her and explaining it was the result of an intense assignment that created a very strong emotional trigger for you and that you realized you were in a vulnerable state and that was why you were originally calling to take the night off. She may have a few questions, but providing a brief explanation may help alleviate any concerns that she may have.