mrsmo, sympathies. Normal for my dd and ds. They are sometimes called "high needs" babies - Dr Sears wrote a whole book on them: here. Saved my life with dd, as she was my first and no other mum I knew had a baby like her. In fact, the other mothers I know with high needs babies have been on mn!
Sadly, none of the usual tricks, like swaddling or nightie with mother's smell in cot or lovey worked. They knew what they wanted and would not accept anything less. But try anyway, you never know what will work.
The buggy worked. So took them out for walks, if only to get them to sleep. Will your dd sleep in a buggy? The mechanical swing worked as well, for a while.
You are doing great with the sling and co-sleeping.
As for when they can be put down, well it will get better once your dd can sit up (she will be able to play with toys better), crawl, walk. With each milestone, she will get easier and easier, as she is able to do more for herself.
Both of mine were bf babies. I think bf-ing helps, rather than hinders, because of the closeness and comfort it gives. This high needs thing is a temperament thing, and I don't think bottle-feeding makes a difference. hth
Hang in there. Take care of yourself. It will all be worth it in the end - promise.