I just read in Drug Muggers about a correlation between zinc deficiency and panic attacks—which makes sense to me, given how integral Zinc is in all the cycles of the human body (the Methylation Cycle, especially).
I know for me, I recently had my blood run at the Urgent Care, and—despite a significantly low ALP (Alkaline Phosphatase) value—everyone was telling me that "my bloodwork look[ed] fine," too. But, come to find out, when I took the initiative to research what low ALP might indicate (b/c, typically, the attention of the masses is only grabbed when ALP is high), I discovered that my significantly low ALP value could be indicative of a zinc deficiency. ——— My point being (from the impression I get): zinc deficiency isn't something loudly revealed by routine bloodwork (nevermind the fact that the run-of-the-mill doc/psychiatrist doesn't bother him/herself with fully understanding how each mineral/vitamin may or may not integrally affect mental health!).
This post: Anxiety and Panic Attacks – Causes and Correction, by Dr. Lawrence Wilson, also ties Zinc levels (and Magnesium and Calcium levels) to panic attacks.
…and, if not Zinc, I'd look into your Cortisol levels—maybe your Cortisol balance is outta whack and you could benefit from supplements known to help keep Cortisol in check (such as Ashwaghanda).