Storing breastmilk

I've been been storing my breastmilk for my baby.. Matatapos na kc maternity leave ko. Ayaw naman ni baby formula milk kaya pump na lang ako.. Ok lang ba na ganyan way ko istore ung milk ko? Nilalagay ko s tupperware.. May iba dn kcng lama yung freezer ko. Thanks in advance sa sasagot