Sorry to hear what you are going through.

I have used nipple shields with my eldest son, and my youngest. My reasons were that I am well flat I suppose, although after a good feed they are fine,.

DS1, was a sleepy baby, wouldn't attach and now looking back in hindsight the reason he couldn't was because his tongue was too short. I tried a LC and whilst after about an hour she got him on their was no way I could do it at home. He weaned off them at 5 months and attched (mouth and tongue were stronger by then) and I breastfed til he was 14 months.

DS2: He had a long tongue so attached no worries

DS3; He was born, wouldn't attach at all after birth, had a great Midwife also a LC, told her my problem with DS1, she looked in DS3 mouth and said he has minor tongue tie, your too flat no way he will attach well. Used a shield until about 12 weeks, and he now attaches no worries and is fully BF.

My milk supply wasn't affected at all, only issue with shield is that it does probably extend the length of a feed slightly. I was happy with the Pidgen brand, they only are half so bubs can still smell the breast.

Good luck, stick with it and I hope you get through the next few days.