My 6 year old daughter was so excited to go to school today because its her first day, but when we got in her classroom she was crying :( They said its a separation anxiety disorder. Is this normal? How can i help my child with this disorder ?

Very normal. My child is 2yo, and she may sometimes manifest this even if I will only have to buy something outside. But I have read an article which states that wherever will you go, bidding goodbye to our child is a must and it should be short goodbyes. (Yung tipong "alis muna ako balik din agad si mommy" then alis ka talaga wag ung pabalik balik at titignan mo kung iiyak ung anak mo o hindi) Bec. this might confuse them. Building trust should also be one to consider bec they are so secure with us being around them. It may take time but we should be patient in dealing such.