Could I Have Post-Partum Anxiety?

I've had some issues with anxiety and depression in the past, and years ago I saw a therapist and was on medication for depression.

I've been fine and off meds for many years now, but I'm feeling the anxiety come back lately. I got the baby blues pretty badly right after DD was born 4 1/2 months ago,  but that subsided when DD started STTN at 3-4 weeks old.  

For the past 2 months or so, though, I've had bad anxiety issues though and it all has to do with a fear of DD not sleeping well at night.  There have only been 3 or 4 nights when she hasn't slept through the night since she was about a month old. But I have developed a fear that she'll start waking up in the middle of the night. I associate the possibility of her not sleeping well to the desperately lonely and sleep-deprived feeling I had for the first few weeks of her life.  And even though she sleeps well 99.9% of the time, I can't shake this feeling of anxiety about it.

I'm not very good at not knowing what to expect and I feel that I need to maintain control of most things in order to keep my sanity.  Needless to say, knowing what to expect and controlling every situation isn't very easy when you have an infant.  I've had several panic attacks lately and my DH and I just aren't getting along anymore because I am constantly anxious and overly-stressed.

Does this sound crazy? Am I alone in feeling like this? 

Is this post-partum anxiety?