No weight gain at 30 weeks and worried

Lina
Hello everyone!! I see a lot of you are gaining weight with your pregnancies. I haven't gained anything and I'm starting to worry. I was 135 before I got pregnant and lost 10lbs with morning sickness. I'm 30wks now and only 134.6 😁 my doctor doesn't seem concerned because my uterus and baby are growing. I'm tired all the time and have low iron but she prescribed supplements. 
Any of had that experience, this the belly now