breast milk with formula

Tammara

Baby is 6wks now and has only been given expressed breast milk, but the getting up every 2 to 3 hrs has my body drained. so today I decided to start giving her enfamil ready mixed (gentlease) formula. she's so upset (crying and frowning) that I'm giving this to her and I read that I can add a bit of breast milk to it I did that and it seems to work a bit. has anyone tried this method?