Breastfeeding milk supply

I’m worried that when baby comes, I won’t be producing much milk to breastfeed due to REALLY low iron because my aunt wasn’t able to produce any milk cause of her low iron. I’ve forced myself to take my iron pills but it only causes me diarrhea and vomiting almost all day.

Did anybody have a problem w/ not producing milk cause of low iron? Also, does anybody know what to take by experience to increase milk supply?

My first child, I was able to breastfeed till 5mo, then my milk dried up. My second child I didn’t even reach three months yet and my milk dried up. So my third, I’m curious yet worried. I’d like to breastfeed for about a year...