Hello and I hope I can help you today. It is normal to have very low blood pressure when you are pregnant. When you eat a big meal, the blood from your body is shunted to your stomach to digest your food. This can make your blood pressure drop even more, especially if you were lying on your back. This is why many people get really tired after a big meal. You just got an extreme version of this that made your pressure so low you almost passed out. The way to help prevent this is to stay upright for at least an hour or so after a meal, and to try to lie down on your left side (it puts the least pressure on the large vessels that bring old back to your heart). Also, make sure you drink lots of water to prevent dehydration and take your vitamins. I hope this reassures you and that I was able to answer your question. Best wishes for the rest of the pregnancy, Dr. Brown