ABA is the Australian Breastfeeding Association - there's a website you can look up, there should be a link on this site to it somewhere, too. It's been invaluable to me. I was lucky enough to be subscribed by DP's aunt and uncle, but recently resubscribed myself because I can't imagine being a mummy without my Booby Club and Booby Friends now! It's a fantastic organisation and you don't even need to be a subscriber to go to meetings or call a counsellor (but it would be nice!). The thing is, it's local people, so you have people nearby to draw upon when the going gets tough.
Sounds like you're going a good way about this - great that you have some space and time to think, too. It's good practice now to use your emotions constructively, because you'll be of very little use to a small baby if you curl up in a corner after letting everything run away from you unaddressed! But the curling up to your sister bit sounds like it's a luxury you've had to date, and it sounds like you know it's time to be the mummy And I think your sister will be there anyway, should you still need a good curl up!
You may not want a partner involved, but you have got gold there with your family. Life is more than just about you now, and it can be a scary thought, but it should be more a thought that puts things from the past into a neat little place. Lots of things start to make sense when your preggers - you may think you're going batty (and in some instances, that might be true!) but I know a lot of women, myself included, who achieve moments of lovely clarity.
Pregnancy will take you to some cool places in your head and heart, so feel free to share that with us, and with your 'Due in October' thread!