Don’t give yourself too much pressure. Breastfeeding or formula doesn’t determine whether you’re a good mother or not. If breastfeeding is taking a toll on you, it’s totally fine to formula feed.
Anyways, if you wanna give it another shot, you have to constantly pump (add in power pump if you need to) even if there’s nothing coming out. It’s gonna be tougher but this is the only way to signal your body that it needs more milk. Drink more water, take supplements and most importantly, don’t stress.