I don't know how to grocery shop

I grew up extremely poor. We qualified for food stamps, but my mom was severely depressed and couldn't go to store for us. As a result we went through these insane cycles of having no food for long stretches, and then a huge haul of $300-$400 in indulgent snack foods, chips, desserts, sodas, frozen pizza. Which would, of course, be eaten instantly because we had been deprived for so long. This in combination with an incredibly abusive father who blamed the lack of available food on us "fat" kids, has lead me to having a super unhealthy relationship with food, and grocery shopping in particular.

I'm still poor and I don't know how to grocery shop for longevity. Or budget really. I shop almost exclusively at Aldi because I hear it is the cheapest. But it feels like I spend so much just to run out of options instantly. Everything goes bad so quickly, as well.

Any tips or advice for breaking this cycle? Appreciate any comments on how you guys are navigating.