Breast milk is best for your baby. But if you have to supplement, it will be okay. Our daughter was premature and I had so much difficulty with breastfeeding. Just to get her to suck was an issue. Yes, she had some nipple confusion, but we worked through it together. I recommend you see about calling a lactation consultant if possible. The hospital where I had my daughter had one on staff that did some free sessions with me, so you may have options there. Also I spoke with several over the phone and they never charged me a dime. I also went to some of my friends houses that just had new babies and they helped me as well. It's hard to say what is going on with your son without seeing it, but I am confident that you can do it.
I was so worried about my latch, my latch, my latch -- but when I stopped messing with it -- my daughter did it just naturally. I didn't need to do no trick to get the nipple in far enough -- after one second she got it.
As far as you milk supply, are you using nipple shields? The shield was invaluable in getting us started, but it slowed down the milk flow and lowered my body's milk production.
It took 4 weeks to get my daughter to latch on and take milk from me. 2 1/2 months before I stopped using the shield. During all that time I had to supplement with pumped milk and formula with a bottle. My daughter is now 15 months and she is still breastfeeding and she prefers the breast to formula, its her special time with mommy. So long story short if you to introduce the bottle you can just continue to work on the breastfeeding along side it and it will be ok.