Breastfeeding tips?

Help!!! I fear that I started on the SNS system too early and now it's too late. My baby is so used to the convenient drip of the system for about a week now and he doesn't suck hard anymore on my nipple when I'm trying to go to sole breastfeeding.  I've had tips left and right about how to get on the right track again, but the nest has been so helpful throughout this whole pregnancy that I thought I would hear suggestions from this group.
Any advice would be appreciated.

Thanks in advance!