Hi T.,
When my daughter was 19months old I was in a very similar boat. She was still feeding very reguarly throughout the day and every 2 hours at night. We co-slept too and I don't remember when she worked out how to get to my breasts when I was asleep, but it only took her to break off 2 bittons before she learnt how to unbutton my top.
I admitedly did not try to do anything about it until she was closer to 2 and I have not totally weaned her yet (she is almost 3) although we have got her in her own bed (introduced that at 2) and I go to sleep in her bed when she wakes up now which is somewhere between 2&5am (anywhere from 6-9 hours of uniterupted sleep. So I do not have what some peopel may consider the ideal situation, but it is ideal for me.
So what I did was....
When she wanted a breastfeed (which she calls 'nana') I started asking - "Why do you want nana? Are you hungry? Are you thirsty? Or do you just need some loves?" I would then offer her a snack, water or cuddles and something else she might love - like a story. She started to learn if she was hungry and would respond asking for food and sometimes she would say "I just want Mummy" and when she got a little older she would tell me it was because she was tired - she still goes to sleep with "nana". Sometimes she would say she just wanted to drink mummies "nana". So far this has worked well for us and now she only feeds at night or during the day when she is trying to go to sleep (very irreguarly).
I also try to get her to stop continual sucking when there is no or little milk coming out by explaining to her that mummies 'nana' are sore and if she keeps sucking she won't be able to have more later because they will be too sore. I then tell her to have onelast suck and to please let go. This has allowed me to shorten the time she feeds at night and after she has fed for about 10 minutes I will lie with her. She will often then tell me she is hungry so I get her some yogurt, banana or a wholeweat cereal with no sugar whcih she eats and then goes back to sleep. The same techniques is working well in the middle of the night and I have found when she goes to sleep after just eaten some carbohydrates and with some cuddles she sleeps better and longer.
FOr me this has been a long process and took months to get to where we are, but it started with me deciding that I could not work any longer with her feeding all the time. I started working in the home environment looking after other kids when she was 12 months old and all the breastfeeding and looking after 5 kids under 3years old from 8-6 5 days a week started getting to me and I was getting incredibly tired.
We still have our battle of the wills, but have very little crying and she has been taught that she just needs to learn (and I will help her) to communicate her needs and wants more in order to get them.
I don't believe in letting a child cry it out and so worked out other ways to set the boundaries and let her know who was in charge, while giving her some areas where she could feel like she is in charge - like would you like an apple,orange or banana for morning tea? Which skirt/pjamas/pants etc. would you like to wear today?
Good luck and don't feel like you have to give up on attachment parenting or breastfeeding to get your energy back.
I would also suggest that you get at least 1-2 hours a week time out where your husband has the child and you go out and exercise, have coffee with a friend or do something you like to do by yourself. It is a huge rejuvinator!!!