Please help. Stopping diclegis

I'm 16 wks today. Battled horrible nausea and vomiting since week 6 so needless to say I'm pretty fed up and discouraged. 
Anyway, at the peak of the nausea I was taking 3 pills of diclegis (aka diclectin in Canada) and had a few days of feeling great so stopped it cold turkey. (Around wk 12). That was followed by one of the worst days of my life and I read online that it could be withdrawal. So I got back on it and weaned off till 1 tab nightly for the past 3 weeks. Again felt ok yesterday so didn't take it last night and I'm suffering again. Vomited twice before noon. 
I'm 16 wks already. Is this REALLY withdrawal and I need to tough it out until I stop? Or does my body still need it?? Did anyone stay on it their entire pregnancy?? I want to minimize pills but every time I stop it I spend my day vomiting and crying and just utterly miserable. Help pleaseeeeee if u have any experience with this.