I used the nipple shield with my son (who is two years old now) until he was eight weeks old. I too wanted to stop using the nipple shield as soon as possible, but it was tricky because of my anatomy more than his mouth or latch.
Do you have a lactation consultant, midwife, doula, pediatrician or Le Leche League leader offering you any support or input on the issue? Has anyone definitely said it's your child's latch that's not right?
The reason I ask is because what finally worked for us was the Lansinoh nipple extractor, again because the issue was my anatomy, not my son's latch. The day I used the extractor was literally the day we stopped using the nipple shield for good. A breast pump would probably work as well as the extractor, if there's any issue at all with flat nipples.
I'm so sorry it's become frustrating for you and that you're beginning to experience clogged ducts. I had a run in with mastitis while using the shield, so I understand wanting to get off of it. But more than anything I was just sad about having to use the shield because we weren't nursing the way I had anticipated. Ultimately, I had to tell myself that I was still giving my son the best even if it wasn't exactly how I wanted it to be.
I hope you find out very soon what the issue is. You are doing such an amazing job! Motherhood, especially if this is your first, is so unpredictable in those first weeks and months. And no one - NO ONE - tells you about nipple shields or colic or latch issues or reflux when you're awaiting sweet baby's arrival. So we are required to shoot from the hip and make huge decisions on very little sleep with the best information we can get from people we hope we can really trust. It's a wild time, but you are doing so well and reaching out for help here is a great step as well. I've gotten so much amazing input and advice from mommas here.
Best wishes to you and your sweet baby, who, by the way, is nursing at very normal frequency for an infant. Sounds very healthy!