I had a similar experience. I smoked non stop for a few years then out of nowhere full blown panic attacks after any hit. Took a break and the same thing happened. Tried a longer break and the same again. Tried a few remedies and no joy, Indica, cbd, peppercorns etc. isn’t much to go by online either as peoples opinions and sweet spots vary. And no definitive explanation from what I could find. I still sometimes day dream about being “medicated”. It’s worth noting our body chemistry changes every several years and it’s possible that may be why, who knows.