Constipation Due To New Prenatals

I Posted Yesterday About Starting On These New Pills That The Doctor Gave Me But I'm Not Taking Too Well To Them. Ten Minutes After Taking Them This Morning I Threw Up The Whole Pill And All The Water That I Drunk With It ! And Now My Stomach Is Hurting And I Am Badly Constipated. I Go To The Doctor Friday But Until Then Should I Continue To Take Them And Is There Something Super Special In The Prenatal Pills Given By The Doctor Vs OTC Prenatal Pills ?? Because If Not I'm Going Back To My One A Day Women's ! What Do You Ladies Think ??