Nausea is definitely one of the symptoms that comes along with migraines. My experience is that the amount of time it's present really varies. But I guess overall for me it lasts several hours, sometimes for the entire migraine. Everyone is different.
If you feel nauseous before the imitrex, it is the migraine causing it. Talk to your doc about getting a medication that will help take away the nausea. You are miserable enough w/out feeling nauseous too. The imitrex should really decrease the nausea, if it works well. If the imitrex is not working, ask the doc about another migraine med--there are lots out there and each one will work differently for you.
Things can be better.
I HAVE HOPE
Many challenges, lots I am thankful for.
spina bifida dx age 20, chronic back pain (surgery: tethered spinal cord, spinal fluid leak), neurogenic bladder (augment w/ stoma, sling-2015), chronic migraine, TMJ, bulging discs etc C3-C6, neurogenic bowel, colostomy-2015, bipolar type 2, anxiety, fibromyalgia, severe nausea, hysterectomy+salpingo-oophorectomy 2015, and more. Gonna be ok!