Weight gain

Chynna • Baby boy arrives June 10th 💙👶🏽
So I'm 20 weeks 2 days and at my first appt (8 weeks) I was 148 and now at my last spot 2 days ago I'm 152 I've only gained 4lbs my whole pregnancy. My dr hasn't said anything but that doesn't seem normal does it? Or is it because I was already slightly overweight before I got pregnant?