OH Bunnyhugger,
Where does one start! Firstly, I'm sorry you are going through such a rough patch. It is not easy for a parent Nor a baby/toddler.
What you are experiencing is perfectly normal. There is nothing wrong with your daughter. Remember, she is only 13months old
I'm still bf my 2yr old and that is how he falls asleep at night and needs that comfort sucking when he wakes up during the night. Personally, I am fine with that. It does make me exhausted at times, I won't lie but I know how deep the connection goes with bf. We co-sleep as that is what works for us. It is not easy to wean them by your personal choice. Self weaning is easier on their emotional state cause your breast is a mothering tool, not just for feeding. It is your daughter's comfort, security and feeding tool. It takes away pain, fear etc

I know a lot of mommies do the don't refuse, don't offer approach but it is a bit harder when they need it to fall asleep.
As for sleep training, I'm personally not a fan of it. I don't believe in it BUT again, I'm not judging you at all. I have 2 kids and know how hard it can be when lack of sleep is your new friend. I know you said, you never left her to CIO (cry it out) and good on you as it is not good for them in the long run. I will attach a few articles on here just for interest sake.
Just also for interest sake, so many parents expect their babies to sleep through at such a young age and again, I'm not saying that is what you expected but the normal age is from 2-5yrs only. I will post some articles on that as well if you are interested. The articles are there for you to understand how normal everything actually is and once you understand that, you will be more comfortable and less stressed about everything.
You can either look at co-sleeping with her and see if it makes things easier a bit and again, nothing wrong with sleeping with your toddler. They were inside of us for 9months. Now, they entered this big, scary world and they need that reassurance from us! They go through 10 wonder weeks before the age of 2 (google it, it is very interesting), developmental milestones, growth spurts etc. It can make them fussy, disturb their sleep and so on. Separation anxiety also kicks in roundabout 15-18months but can start earlier.
She is also sensing your anxiety and frustration. Try to relax more. Get some rescue remedy, restin or rhodiola. It is all safe during bf. The last one you will only find at a health shop. The other two you can try dischem or any other pharmacy. When you feel like you going to lose it, give yourself a time out mommy. Step away, go outside & take a breather. Aha Parenting is a wonderful parenting site, which I will attached as well. Just go to drop down mention for parenting tips & also ages and select whatever you feel like applies to your current situation.
I really hope you will find something that works for you & your daughter
Just a side note, remember, a formula fed baby can be dependant on a dummy or bottle as well so don't think there is anything wrong with your daughter being attached to your boobie!
www.ahaparenting.com/
www.phdinparenting.com/blog/2008/7/5/cry...t-is-not-for-us.html
www.examiner.com/article/study-shows-bab...-out-remain-stressed
www.isisonline.org.uk/how_babies_sleep/
www.isisonline.org.uk/how_babies_sleep/n...l_sleep_development/
www.isisonline.org.uk/how_babies_sleep/w...es_sleep_as_they_do/