Diarrhoea twice a day for 3 days/week.

Hello, I'm currently 21 weeks pregnant.  I'm having a gastric problem since the 9th week. During my third month, I had loose motion once every day. In the 4th month, it automatically stopped, and from the 5th month again, loose motion has started, Im having at least 2 times every day, and even I take non veg, it's like 5-6 times. I feel dizzy and tired, but I keep myself hydrated by drinking 4lts of water every day , taking glucose. Due to this I have not gained any significant weight till now. Before the start of pregnancy, my bmi was normal, and I was on weight loss journey that I reduced 6-7 kgs for pregnancy. My concern is how to stop loose motion and will baby be impacted because of this? All the gyn and obs I contacted said me loose motion is due to gastric problem and will eventually subside