stock pile?

is it too early for me to start a stock pile? I'm 7weeks and last pregnancy i miscarried at 10.. I'm praying this baby sticks! & when it comes time to birth Im afraid I won't have as much money as I do now. I want to start stacking up on formula (I do want to breastfeed my first pregnant my supply went low in 3 months) and diapers! If so, do you think the formula will last until summer