Weight loss issues

I'm having a serious problem with losing weight this pregnancy, I've lost roughly 20 or more pounds so far. I'm no skinny girl but I'm pleasantly chunky so weight loss wouldn't hurt me. I'm just concerned about it, my dr is too and changed my nausea meds so I'm no longer constantly throwing up and I'm eating normally with a couple added snacks throughout the day. But I am still losing weight and it's getting worse the more I eat. I plan to talk this over with my dr next week at my appointment but I was wondering if any other mommas struggled with this problem. Baby is growing fine, not super active but still moves around normally, I eat pretty healthy and take my prenatal vitamin religiously. I lost weight with my first baby but not like this and I'm unsure what to do