Hi Pheonix, I'm feeling your pain! Bloody tough eh? Definitely keep up with the swaddling, mine usually cry once I've swaddled them, but they settle quicker if they're well swaddled, if they get a hand out they try to suck it but then get frustrated with it and won't sleep. 5 and a half weeks is very early days, it will get better, mine are now 11weeks and one of mine has slept right through a handful of times, not consequtively though and the other has managed six and seven hour stretches at times. I do try and make them wait in between feeds - not letting them cry but I don't feed them if they're just grizzling a bit. We did a stint of formula feeding at night but it didn't make any difference for us and was too much hassle.
After weeks of frustration having difficulties settling them early in the night, we discovered a couple of things that made a difference for us. It seems to be important that they get a decent amount of naps in the day and that we get them upstairs by 6pm to start the night feed - we've found that babies that are over tired are very difficult to settle and they have more unsettled nights. Sometimes we'd be three hours getting one of ours to go down. (we aim to get them to have four or more hours naps in day - it's a struggle and I often end up carrying one or both round in slings just to get them to stay asleep)
We've managed to get one baby to take a dummy, and the other will sometimes settle if offered a little finger to suck on.
We also use a white noise - womb sounds CD that we leave on all night - not sure how much difference it makes, but babies aren't used to sleep in complete silence, so maybe it's comforting for them.
We had been routinely waking them at 11pm for a night feed to help them go further, this didn't seem to work for ours, when we stopped it they didn't wake at 11 but just slept to the time they had previously been waking up at naturally, so we were just making extra work for ourselves.
One of mine is not such a good sleeper, she will often wake 30 - 45 mins after going down, she will usually go back down after a little extra feed. Babies cluster feed in the early evening to stock up for the night ahead, so we look on this one as just a bit more cluster feeding.
In trying to do the best we could for our first son we inadvertently taught him to wake frequently for feeds in the night. we really struggled with him and he's now 2.5 and still doesn't sleep that well, so we're trying to do everything we can to make sure we don't teach our twins any bad habits, but we're not fans of leaving them to cry so you have find some way to soothe them that gives them the least help but doesn't cause distress for anyone.
Sorry I've gone on a bit - got on my hobby horse! We've had a hideous weekend - toddler up with vomitting and diahroeah (not sure on spelling!) and lots completely histerical tantrums in the day. And today an outing to the dentists oh joy.