Don't give up. It is quite natural to slip slide into what you used to do
It does take a bit of effort to think through at first.
I sometimes buy more than I need of sturdy breakfast foods. There are two tubs of oatmeal in my cupboard now and a huge supply of eggs berries and apples. For me it works to be a little bit ahead of myself and over -plan.
On step one I used to carry healthy tasty snacks with me.
You will soon feel benefits.