You are doing the right thing getting all those medical tests. The first thing to do is rule out a physical cause. On the psychological side I would think back through October and see if there were any major events that took place — particularly any events where you experienced a loss. Losses tend to happen around the time of panic attacks. They seem to set them off.
In fact, it could be simply the fear of losing something that can do this. Potential break ups with boyfriends, the fear of death of someone close, the loss of a friend moving away — any potential big loss can be deeply unsettling.
Allowing yourself to think about what may be the trigger for these may give you an idea of the source. If you find something that might be important — talk about it with the psychologist. But as you explore these other possibilities please continue the medical tests. You want to rule out the medical issue first.