first month of separation

Well, the first month of separation has been great for me, for the most part.  We were separated within our home for several years before he finally moved out. Huge relief in not dealing with that stress every day all day.  My worst time is when I suddenly find myself alone - and panic that I will always be alone!  My schedule and my kids' schedules are all so busy - that when I have alone time that I know is coming - I'm thrilled.  It's the unplanned alone time that gets me.  How do you cope with that???