Whoa, you and the other commenter are the only ones I've ever met who even remotely relate to this though (I've never bothered searching it out on the net). That's actually kind of a relief. For me it also coincided with just higher anxiety in general so I'm not really sure which came first.
If you search "weed panic attack" its all over the place.
I wondered what happened to me for a while and I tried different strains/methods but it was all the same. The only thing I can think of this seemed to have started after a semi bad experience with MDMA and weed.
It's fairly common. Works great then one day, boom, pure anxiety hell. I went from being my happiest ever to taking years to just feel "ok" again