I was just reading about it and I guess hypervigilance can occur with other anxiety disorders, but it is most closely associated with PTSD.

You might look into Bipolar II also if you're not familiar with it. But the type of hypervigilance you are describing is not a symptom of BPI or BPII so that is being caused by something else.

The mind is a very messy and muddle place... at least mine is as well