Feeding

Hi moms! I'm sorry if this turns into a long story, bear with me. My 1 yr old refuses to eat. We started having problems with constipation at 1 1\2 months. Tried every formula, nothing made it better. We started purees at 4 months. He would do fine for about a week and then he would eat a lot less for over a month. He tested positive for anemia at his 9 month check up and lost 1 pound at 10 months. At 1 yr old, he still refuses to eat and still has constipation. His ped finally referred him to occupational therapy. On monday, my husband and I decided to take him to a pediatric gastroentorologist in Mexico. The specialist was great, but he put my LO (little one) on a very restricted diet and prescribed a laxative. A lot of people have recommended this dr which makes me hopeful, but I'm having a hard time with the diet. LO (little one) throws all food on the floor and refuses to eat anything new. He cries because he's hungry, and still won't eat! Has anyone else gone through something similar? How did you deal with it? How do you get LO (little one) to eat? He's only been to 1 session of therapy and we just started his treatment from the dr in Mexico less than 5 days ago.