Loosing weight

Have lost almost 4lbs in a week. I'm not vomiting my food back up so I am concerned with why I am still loosing. I'm down lower than ever. I'm not able to take the prenatal vitamins or Flintstones. I was doing a little better so I tried them again and it has put me back into dry heaving and constant nausea. Waiting for my OB to come back from lunch to see what he thinks. 😏 Confused, scared FTM. My family and inlaws cannot seem to tell me enough that I'm hurting my baby. Even though I'm doing everything I can to stay healthy for my little baby.