Lots of (((hugs)))
It can take up to 14 days to see full improvement. However since you had a great feed followed by a regression I would try a chiro or osteo - tongue tie can cause musculation tensions in the jaw.
Did they teach you stretching exercices to reduce the risk of reattachment?
Obviously it is up to you and if you want to quit that is perfectly fine. But I can Tell you that it will get better, you are still early days and as I said it can take some Time before LO learns how to use his new tongue.