Second Trimester Weight

I have Hyperemesis so I have lost 30lbs since the start of pregnancy. I am 14 weeks. My doctor knows this but hasn't weighed me during the pregnancy at all. I have lost 2.5 lbs this week due to a lot of vomiting/food aversions. I don't know when I should bring this up or when it becomes dangerous to continue losing weight. I am in the healthy BMI range. I am not a small person (5'9", 135lbs/165before). So maybe since I have curves it doesn't seem too intense to my doctor? Anyone out there know what I should be doing or when this becomes dangerous to baby?