Temper, Tantrums & Crying !

hi... I am a mom of a single 6 yr old girl and nw am a stay at home mom (having been a career woman for close to a decade) ..Over the past 5 - 6 months or more, we  have seen our child exhibit unbridled anger for almost all things at home - eating / waking up in the morning / dealing with TV schedule / homework and cries at the drop of a hat. We have her grandmom living with us for close to 4 years now, and they used to share a special bond. Outside at play, she is jovial, but the moment she enters home either from play or school , its unrelenting anger and cries at the drop of the hat.. She doesnt throw too many tantrums, but in increasingly becoming very very difficult to handle.  

She seems to constantly go out on vacation, enjoy life and not do things as soon as she is told to. Academically there is no pressure or issues at school or with friends.

We come from a value based family and do cater to most of her needs and as a couple, me and my spouse do not quarrel etc in front of the child. I have reprimanded her sometimes to keep her anger in check. but its getting out of control. 

Please help .. am very confused and anxious

Sunshine Mom