YM, I didn't manage to bf my 1st or 2nd dc but have established it brilliantly with my 3rd. A lot of it IS confidence in your body's ability to do its job, because once you stop doubting yourself you realise that it is going okay and you're doing okay.
I gave up at 3/4 weeks with dc1&2 because they hadn't regained their birthweights, and I thought I didn't produce enough milk, thanks to my HV mentining Failure to Thrive at every weigh in. This time it took dc3 6 weeks to regain but he did it without the aid of formula and with the help and reassurance of 2 bfcs and lots of MNetters. That is very unusual but everything else was okay - he was alert, content after feeds, weeing lots, pooing regularly, etc, so I just kept going. I used the NCT bfc line but there is also the La Leche League or Association of Breastfeeding Mothers and another I can't remember off the top of my head.
I think the one thing I did differently this time was just to put him to the breast everytime he so much as squeaked for about the first 6 weeks. It didn't matter if he'd only fed 5 minutes earlier, he got a boob in his mouth! It did mean I was literally pinned to the sofa 24/7 but it's been worth it. I just accepted that that was had to happen if I wanted to get bf established. Dc1&2 watched far too much telly and didn't get as much attention as they were used to but they don't even remember that time now.
DC3 is now 14 weeks, finishes feeds in less than 10 minutes, I never have to worry about taking enough bottles when I go out, spend no time doing the endless washing/sterilising/making up bottles. Those first 6 weeks were worth the struggle for the simplicity of life now.
I also co-slept as it made the sleep deprivation slightly more bearable, altough it took a bit of practice to get the hang of feeding lying down.
The best advice I was given was to take it one day at a time. Don't set yourself any long term goals, just aim to get through that day. I had quite a few days when I was so close to giving a bottle but told myself I'd do it in the morning and by then I'd come through that little crisis and didn't need to.
There is so much info on here, I spent ages reading through the archives, finding out about estalishing bf; what was normal, what was a problem, what was old wives tales, when to listen to the mw, when to ignore them. It helped so much to be well informed beforehand. Kellymom.com is also a great website with masses of accurate information. I'd have a browse through that too, if you have a bit of time.
Sorry, I've gone on and on but I'm so amazed to be bfing and feel so good about my body, compared to how down and gilty I felt after dc1&2 that I want everyone to manage it!
Good Luck, have faith in your body and your baby to do this!