I had the same issue. It was the brand I was taking. I don't recommended bunnies because I tried them also but stopped them once I realized that lacked TONS of vitamins the baby really needs like calcium and potassium. I take centrum prenatals and they are a life saver.
Im 12 weeks and i have the same problem. I have to eat in the morning and then take it and i had to switch to gummy vitamins
Take them before bed, and never on an empty stomach.