I had this happen to a young, male patient in Afghanistan. Presented to our clinic with sudden onset, non-exertional angina. History was significant for smoking and moderate ethanol use. No known past medical issues or familial history. Ran a XII lead and he had some non specific ST changes and a left bundle branch block in addition to runs of sinus tach in the 130-140 range. Worked him up as an ACS. Gave ASA, NTG and loaded him with a Beta blocker. He was evacuated out and worked up in a military hospital. XII lead was normal, enzymes were negative and symptoms had resolved. He was discharged back to full duty. Saw him again a few days later with an identical work up. Again, the military hospital found nothing and told us our ECG machine was probably not calibrated. It occurred again and because it was close for him to return home on leave, he went back home and did a cardiology follow up. Subsequent follow up revealed he was diagnosed with vasospastic angina but well controlled on meds following the diagnosis.
I'm glad you are feeling better.