What happened to my milk??

Trying to make this short... My daughter was born 3 weeks early with a weak suck and a horrible tongue tie. Her blood sugar was low and she was tiny so they gave her a bottle right there in the delivery room. Her latch was awful, she hated the breast and so I pumped my milk in and bottle fed her. We had to occasionally add formula too, but i pumped almost enough for her. Then we got the tongue tie clipped and started using the nipple shield. Suddenly she loved breastfeeding! But she still couldn’t latch without the shield and she wasn’t drawing enough milk from me to gain weight so I had to keep pumping and supplementing and adding some formula. We kept trying to remove the nipple shield but no luck. Then after a couple of weeks we found out that her tongue was still too tight and that was the reason the latch was still bad so yesterday they clipped it even further. They told us to keep up the same routine with the nipple shield and pumping and supplementing until our next lactation visit on Wednesday so that’s what we’ve been doing since yesterday. Well today I can hardly get anything when I pump. Like I’m getting a half ounce. It’s pathetic!!! What is going on?!?????!? Could it maybe be that this clipping did the trick and she’s sucking me dry even through the shield?? If not then what is this?!?!?