My daughter is five years old and in in kindergarten.I was told by her teacher that she doesnt know how to read and write,read simple words ,sentences,write the alphabet ...etc

I help her with her lessons at home and also noticed that howmuch ever she tries she keeps forgetting the alphabet,their sound,and the way they should be written.I have to guide her each and every time.

Is this learning disability?Whom should i take help from?...Please help...I am really worried.