Tongue tie help

My son is 7 weeks old, when he was still in the hospital the pediatrician informed us that he had a tongue tie so we had it snipped when he was 2 days old. However, he is still unable to latch into my bare breast and we've been using a nipple shield this entire time. He is exclusively breastfed, from my breast, but only with the nipple shield. I'm trying to see a lactation consultant but I'm worried that the tongue tie grew back or I missed something and that's why he's still unable to latch. I'm worried that he's not eating effectively because he nurses for very long periods of time and doesn't go more than 3 hours ever without wanting to nurse again. During the day if we are sitting at home he wants to nurse almost constantly, and that night we're still not getting any stretch longer than 3 hours of sleep, which at almost two months other moms seem to be experiencing with their breastfed babies. I know he's getting enough milk because he's gained weight and he has lots of dirty diapers and he is such a great baby with a great temperament so I know he's not hungry. I'm just feeling bad for him that it's taking so much work for him to eat and sad for us and didn't know if anyone else had been in this boat, via the nipple shield and tongue tie situation. Thank you!