I had this for weeks and it was so bad, turned out I had an infection and that I was lactose intolorant, caused by the pregnancy.
My doctor advised to go to the chemist and ask for 'UltraBiotique' by Nutrisantw labs. It's a natural hernbal remedie for this and will not effect your baby.
Try not to eat any dairy products esp milk, eat dry foods like rice but stay away from breads. Just drink water and nothing else, keep to fresh foods rather than ready made but don't eat anything rich and no sweets/chocolates.
You should see a diffference within a few days but I would advise to see your GP, it wouldn't be to do with the pregnancy but more to do with your food intake, maybe a bowl infection or you have a tummy infection. Unfortunately, pregnancy's are a pain when it comes to making us mums suffer lol