1) Acid indigestion 2) Aggravation 3) Agitation 4) Antacid target 5) Antsy feeling 6) Anxiety 7) Anxious feeling 8) Bad gut feeling 9) Butterflies, so to speak 10) Dyspepsia 11) Emotional distress 12) Feeling of anxiety 13) Gut feeling 14) Gut reaction 15) Heartburn 16) Heebie-jeebies 17) High anxiety 1) Angst 
Agita: Heartburn, acid indigestion, an upset stomach or, by extension, a general feeling of upset. The word is Italian-American slang derived from the Italian 'agitare' meaning 'to agitate.'
agita, agit. Shake. A medical or prescription instruction.
heartburn; indigestion. · agitation; anxiety.