need advice with breastfeeding

I couldn't really find what I was looking for when looking through post but I really need to some advice with breastfeeding. my little girl is a month tomorrow and breastfeeding has been a very long struggle for us. she was three weeks early and wouldn't latch to save my life. so the nurses gave me a nipple sheild. (which I also used with my first daughter whom I didn't make it but 2 months breastfeeding with latch complicstions) but she wasn't interested in that either. finally once home I finally got her to eat with the shield. somewhere along the way she didn't seem to be getting much and didn't really want to use it anymore so we started trying just breast again. to my suprise she actually latched a few times but as soon as she does she pulls her head around and pulls back and comes off. I try to hold her head still but that just makes her extremely upset and she screams and cries. if I'm lucky she will stay on for a few min and then seem content after the feeding for a few min and then wants more but refuses to latch after the first time no matter how hard i try. I do pump a few times a day but I have a 2 year old so it's extremely hard to pump as much as I need to. does anyone have any advice on how to get her to latch or tips for exclusively pumping? I want her to have breastmilk so bad but lately I'm so emotionally drained and stressed from it I just don't know how long I can continue trying i just don't want to let her down.