severe stomach pain

HI. My daughter is 13 and dx with celiac 1 month ago. She has been on gluten free diet and has only gotten worse. She has severe stomach pains and headaches. THe doctors want her on vitamin D, calcium and a multivitamin but we cant start that since her stomach is in such distress. They also want her to take more milk but she cant tolerate milk without lactaid. We put her on probiotics but nothing seems to help. Does anyone have any suggestions? How long can this pain last and what can we do for the headaches? She is being home schooled and is so sad.