well, my depression (which manifests as anxiety) can be affected or kicked into high gear by my blood sugar levels. If you were vaguely nauseated by stress, and didn't eat, then you may have felt worse - which made you not eat, etc.

Skipping meals or shorting myself on sleep can set off a symptom spiral - all my meds can do at that point is buy me time to get those wobbly neurotransmitters back on track before they go off the rails completely.