30+4 and experiencing very bad nausea and constipation ..

My Ob gave me some Diclegis which worked great but has no more samples... she prescribed me a month supply but it would be $360 and I can’t afford that.. I heard of taking vitamin b6 to help with nausea but could only find a 100 mg one. Anybody know if that’s okay to take? Maybe half a pill? Ob won’t be open until Tuesday or Wednesday but can’t wait that long to find answers ..

I am definitely eating and drinking enough so I know that isn’t causing this problem.. are there any foods or medicines I could take for constipation ?

Thanks for your guys help !