Struggling with nausea

Bethan • Married 4yrs with 4yr old Boy. Pregnant with TWINS!!! after TTC 2 months. Very nervous about this time after awful pregnancy and terrible labour & birth.
Omg am 10w2d and am seriously struggling with the 24/7 nausea. It's going on 6 weeks now, I can't do anything, go anywhere. Work is a nightmare. It builds and builds till I'm crying, then the gagging starts and them am sick. Eating helps a little but only limited foods like cold toast and cold cooked plain pasta. Everything else makes me gag. Walking or driving makes it worse like motion sickness. My doctor will not prescribe me anything. I don't know what to do anymore.