I have those feelings as well. There are days that I miss him - I miss the "normal" life I had before our split. BUT...let's get real here....that life that we had together may have "seemed" normal - but that is not the kind of normal I really want. I guess I was just not wanting to let go of the person that I loved and cared about. I realized that the relationship had been lost. And since I can't change him - I had to focus on me.
As was mentioned earlier, you just need to find something to fill in the cracks of your life right now, to fill that void that him leaving has left you with. And it can be done! It does get better! and it does get easier!
For me, I wasn't sure what all I wanted to do with my life or where I wanted to go. I had been living around my AH for so long that that was all that I knew. I started out slow but I can tell you that I have had a HUGE HUGE year! It's been almost overwhelming at times.
AH and I have a decent relationship now. We have to have contact because of our children. And I actually enjoy telling him about my achievements. Of course, this makes him feel even more scared that we'll never get back together - but it also shows him that I will not accept anything less than I want and/or deserve ever again!
Oops, sorry was getting off the subject there. LOL
Hang in there - make a list of goals, things you'd like to experience, things you'd like to do etc. Journaling can help as was suggested. Just keep on moving - one step at a time, one day at a time!