Anxiety can genuinely cause burning stomach pain through the gut-brain connection, especially when it flares with stress, and this pattern fits what you're describing. The "severe dehydration" feeling alongside it is often linked to shallow or fast breathing during anxious episodes rather than actual fluid loss.
Next Steps
Keep track of when the pain comes up against your anxiety episodes, stay hydrated through the day, and eat smaller regular meals instead of skipping them. Please see a physician to rule out gastritis or acid reflux, and a psychiatrist or counsellor for the anxiety itself.
Health Tips
Get checked urgently if you vomit blood, pass black stools, or lose weight without trying, since those need a different workup.