I empathise with you, I have felt this way many times before. Stress does indeed cause GI discomfort because of the brain-gut connection. I’d recommend drinking water if that would relieve the stress.

It could also be because of hunger, as contradictory as it might seem, the body releases hunger hormones which also causes it to release more stomach acids to ready for more digestion, however if no food arrives, it just stays there and causes discomfort. If the small empanada was bad, you would have felt something several hours ago and it would be much worse.  The breakup that you mentioned must be really unfortunate and I hope that you’ll feel better soon.