Weed has suddenly turned on me. Any suggestions?

Over the last few months I had gotten in the habit of 2-4 hits from my vape pen at bedtime. Between that and melatonin and hydroxizine, I had developed a reliable bedtime routine for getting to sleep easily. All of a sudden last week when I got high it was extremely uncomfortable, akin to when you have way too much, even though the dosage was the same, if not slightly less. Around the same time I suddenly had a terrible bout of insomnia that I'm still dealing with.

The last few nights I've gone to bed "clean" without any substances, with mixed results. Last night I couldn't fall asleep and so out of desperation I took two vape hits. It went...poorly: massive anxiety, body pain, just feeling "weird" and "off" in a way that almost had me getting up to call an ambulance. It was *bad*.

I've never had this experience before and I'm wondering what could cause such a sharp, sudden onset of bad effects. Any thoughts as to what is going on?