28 weeks and have only gained 10 lbs

I was 127 lbs when I became pregnant, went down to 124 during the first trimester due to so many food aversions and nausea. Now I’m 134 and my doctor said I am measuring fine but she wants me to gain 15 lbs in 12 weeks. I’m nervous I won’t be able to put on 15 lbs in such a short amount of time unless I eat a lot, but I don’t have a huge appetite, just average and healthy. I seem to be gaining 1 lb a week since mid second trimester, which is good right? What are you ladies eating to put on healthy weight?