pregnant and can't gain weight?

Any suggestions what I could do? My appetite isn't strong and it's hard to find things I'm in the mood to eat I've lost about 10 pounds in the first trimester I'm in my 14 week and right now my bmi is 14. I need to gain a lot of weight and am worried my doctor even scheduled me with a nutrionist but it was common sense stuff I already knew when I went to the appointment.ive always been a super naturally thin person never got over 105 pounds I have a high metabolism. But currently am 91 pounds right now and need to gain for me and my baby 😩 at least 28 pounds she said (id like to gain 40) but don't see that happening did any really thin girls gain weight in pregnancy? Did anything specifically help you?