Suggest Remedy For Blood Disorder

Hello, my son just turned 4 yrs old and has down syndrome. After some routine blood work, his doc called saying that his levels have changed and she suspects hypothyroidism. This was almost 2 months ago and he has an appointment to see an endrocronologist next month. About a month ago my son began sleeping A LOT15-17 hours a day. The other day he saw his doctor again and I explained how tired he has been. He has also dropped some weight. She told me not to worry he may be going through a growth spurt. She checked his hemoglobin while we were there and said it was low. Shortly after we returned home the doctor called and wanted more blood test done. I recieved a call today saying that he is not anemic, it was the doctors secretary that called and could not answer the questions i had. I am wondering if that means there is no problem of if that means there is another cause. I know that children with ds have a 10-15% higher chance of suffering from lukemia. Should I worry, get a second opinion, or just wait to see the endrocronologist next month. Thank you for any help you coould provide.