I think so but I'd also check my temperature if I were you.. but if you don't have a fever then it's probably withdrawals.. I get Shakey if I haven't had my meds in awhile

I definitely get super cold if I miss mine, a bath is a good way to get your temperature more stable again

I got shakey and hot and cold while withdrawing from effexor.

Sometimes with meds like effexor you can get Brain Zaps (I got them after effexor and after duloxitine) if that's what you're meaning? It's a more rare side effect of stopping SSRIs and SNRIs but do happen sometimes

My withdrawal symptoms happen after about 36hrs without my meds. I get hot flashes and sweats, I get irritated and I get nauseated and get diarrhea. I also will get dizzy and get vertigo if I move my eyes too quickly. I've had to make a habit of taking mine on schedule and refilling my daily med sorter because my ADHD-ish symptoms make me forget ALL THE TIME