Have you and your doctor explored and ruled out other causes for your nausea (pregnancy, inner ear/balance issues, etc.)?

Your taper was pretty fast, but your doctor's every-other-day suggestion would have put you into withdrawal every other day. Withdrawal symptoms (headache, anxiety, digestive issues, brain zaps, dizziness, nausea, etc.) are the big tipoff that a taper is being done too aggressively. Often, folks get relief from withdrawal symptoms by reinstating the Effexor: going back to a dose where they didn't have any WD symptoms (sometimes, even upping the dose a bit) and staying there for some weeks to stabilize before attempting ANY more tapering. When they began tapering again, they only reduced 5–10% (or even less) and waited weeks before reducing again.

OTC medications and supplements can help with some of the withdrawal symptoms. I didn't have nausea very often, but when I did, I found sucking on Pepto Bism*l lozenges and eating dry saltine crackers helpful. You may be experiencing dizziness/vertigo; Ben*dryl, Bon*ine, or other seasickness remedies (wrist bands) can reduce/minimize those symptoms.