Losing too much weight


So at beginning of pregnancy I weighed 168 which was a little heavy y for my height but nothing too bad 6-8 weeks in I was weighing about 162-158 from loose stool every day and a little vomiting. Thursday I went to the OB and weighed 162 however today I am weighing 154 after not being able to keep anything down for 4 days. In total almost putting me at 20lbs weight loss anyone else have this and have healthy baby