Separation Anxiety and PTSD Don't Mix

Well, I found out today that my daughter, Caley, is starting to go through separation anxiety when mommy is out of earshot and line of sight.  My wife was taking a shower and Caley was crying so hard a stranger might have thought I was hurting her.  It destroyed my emotional stability completely.  Of course, Caley could sense that I was very upset and she cried even harder.  Anyone have any ideas of how to cope with this?  It's going to be a long few months if I can't find I way to overcome this.  I am emotionally drained after just a few days of this.