Antidepressants are VERY powerful; Effexor affects your brain's neurotransmitters–serotonin and norepinephrine. While reducing, or after getting off Effexor, it takes your brain a while to figure out how to rebalance serotonin and norepinephrine. Some of us even experience extended withdrawal symptoms (PAWS). I have been off Effexor for two+ years; I STILL occasionally have episodes of anxiety and agitation, but my withdrawal effects have improved GREATLY. If it weren't for COVID-19 lockdown isolation and no longer having the distraction of work, I'd probably not even notice them.
My withdrawal symptoms didn't begin until about six weeks after my last tapered dose. I was prescribed Valium short-term by a Care Now doctor when my akathisia and anxiety became overwhelming. She had me take 5mg Valium twice a day for three days straight (I stayed home from work) to "get ahead of the anxiety." Her "get ahead of it" strategy was pretty effective, but she prescribed 15 more tablets to use as needed and I'll take a half for those occasional episodes if they seem to be building.
I did not want to rely on Valium and through trial-and-error came up with a number of OTC medications and supplements that help me and have listed the supplements I take in previous posts (click on my name to go back through and read). The most helpful are l-tryptophan (DO NOT take while still on Effexor) and GABA. Ben*dryl, Bon*ine, or other seasickness remedies can reduce/minimize the dizziness/vertigo. Fish oil may be more helpful than krill oil for brain zaps. Here's a good article re how to mitigate withdrawal effects with supplements–https://www.4mind4life.com/effexor-withdrawal-symptoms.
Back in December, @cp6401 used the term "stress fragile" to describe how so many of us are during the process of getting off/reducing Effexor and even, afterwards. Distraction helps—reading, hobbies, work, chores, gardening, exercise, etc. I am mindful of what I watch (nothing frenetic, violent, or disturbing), read (cozy mysteries, or romances), or listen to (no atonal, or dissonant music)–some things are just too agitating. Also, very important–I learned how beneficial getting natural light to my eyes is to lifting my mood and calming me. I'm not suggesting sunbathing, but getting out and seeing daylight–take a walk, or at least, get out of your house for 5–10 minutes, even if it's just stepping out onto a patio.