I can't say that I've had the same experience but I have had GAD (General Anxiety Disorder) in addition to SAD (Social Anxiety Disorder). While I've always had Social Anxiety - my first experience with GAD was a few years ago. In counseling to deal with SAD, I did NOT realize that my counseling sessions were getting near a topic that I had suppressed (my mother's death from cancer). From my perspective - I was having 'normal' counseling sessions and then WHAM! GAD set in. Suddenly - I could not think. I could not focus. I would look at an email and the words didn't make sense. I was too anxious to concentrate. After an ordeal of a week in which I had to 'fake' working during a stressful time when my boss was away and I was to 'take care of emergencies', I told my counselor I would have to quit counseling because the anxiety was getting to me - but I didn't really know WHAT was making me anxious. I went on Lexapro. This medicine takes about 2 weeks to provide real relief. I wasn't sleeping at night as I waited for the meds to kick in. I had two adjustments to the dosage, each takes 2 weeks to take effect, before I was 'myself' again. Is it possible you have GAD in addition to panic disorder? I tricked myself into revealing the source of my GAD - it was traumatic and I did alot of grieving. I didn't know the source of my GAD was gone because I was taking meds but suddenly I was sleeping all the time during the day. This was because the source of my GAD was gone - I was overmedicated. I eventually went off Lexapro (after 8 months), stepping down in dose every two weeks, and was relieved to discover that the GAD was gone. Then - about a year later I started with the panic disorder. I went on Prozac for the panic and saw another counselor. After I went off Prozac (8 months later) I started using low dose (.25 or .5) Xanax to handle the 4am panic. After 4 months - the panic is almost completely gone and I am going off Xanax. I am having some anxiety - apparently even low dose Xanax can cause that when you go off of it after more than 8 weeks.
So - I am wondering if, on top of Panic Disorder, you are now dealing with GAD as well. I think I have read that some people experience GAD following intense Panic Attacks because they are anxious about another intense panic attack. Hope this added something to consider. Wish I had better info for you.