I’ve had chest pains on my left side and gone to ER and doctors and they brushed it off as anxiety too. Recently realized that my chest pain correlated with POTS flares and my hiatal hernia (but now can tell the difference between them and can manage the chest pain a bit better). Look up POTS and see if you have symptoms and may give you some more direction to figure out what’s going on with you and possibly some things to try to see if it helps to manage. But I agree it definitely doesn’t feel like anxiety or panic attack it’s like body going haywire which yeah seems like a heart attack-I haven’t an actual heart attack🙏🏻 but not sure how else to describe.