How did I end up here?

I was leading a perfectly normal life.  Two kids, two dogs and a house in a nice neighborhood and then one morning I woke up and my husband had died at the age of 53.  No sickness, no cancer, no warning. Just came home the day before and told me he had indigestion.  I didn't think much about it.  I remember being annoyed, because it was a Friday night and I wanted to go out for dinner.  I will never forgive myself for that.  I wish I had realized that he was having a heart attack, but then again shouldn't he have realized that it wasn't just a simple case of heartburn.  At any rate, he is no longer with us and my two daughters and I are left alone.  This was 2 and a half years ago, when my girls were 18 and 15.  Now here we are, my youngest is going away to college in Sept. and I am left alone, no husband and an empty nest.  This was not the way life was supposed to be.   I am too young to be a widow....other people my age are divorced and they say, well they didn't plan for that either.  However, it is completely different, divorce is a choice, widowhood is NOT.