if you're still having problems feeding, have you tried feeding in bed with ds across you so gravity pops his head onto your nipple? (as opposed to having him lie next to you and being sideways on to each other?)
my fab mw showed me how to do both these positions when first trying to bf ds2 and having problems getting him to latch on. To start with, he really took to being on his tummy on top of me, and if you could get the chin to go down in the right place then he would latch on so easily - when struggling with all other positions. Might be worth asking your mw to show you if she hasn't already...
there seemed to be something about the position that was very comforting for the baby - maybe because they were close to your heart and could hear it, familiar from when they were in the womb? and also great for lots of skin on skin contact if you can open up your ds's babygro easily but still leave the back on to keep him warm.
sounds like your dh has got the wrong end of the stick too about having mil there and the way things are going - seeing if you want to go out for tea. Sounds like he is thinking that it is more like a holiday/celebration time; and if his mum is telling him that the baby is really well behaved and sleeps lots in his pram when out, he could be thinking that everything is ok, babies are easy, what's the fuss...
definitely a good time to start a conversation about how things were when your dh was born and 'how you had it easy then, being able to stay in hospital for a week or two even if you had an easy birth...' 
and see if she will recognise that you have it much harder than she did (assuming she had a fairly run of the mill experience from those days!)
I'd also not be afraid to invoke the mw and/or hv (who amazingly have exactly the same views that you do on having rest/others look after you etc) when you want to do something that gets in the way of you doing what they think you ought to do (eg go out when you want to stay in)
Then there's also the baby monitor to consider - you could have a heart to heart with your mum/best friend/imaginary friend/etc and deliberately make sure they are listening to forget the baby monitor is on. Cue angst from you - it's horrible, they just don't seem to get it, think this is a holiday, I'm running around after them despite having had traumatic birth and huge blood loss and not able to bond and feed baby etc etc as per post. maybe they will then realise quite what it is that you are going through.
as for expressing - can be useful even in the early days, little and often to help stimulate supply I found. also when things got really bad and too painful for me to feed it mean there was still bm to drink. You can always freeze it, you don't need to use it immediately, or even throw it away (it seems a shame I know) but especially if one side has dried up a bit, trying to express the dried up side when feeding the other can help.
sorry, lots of random thoughts and things that helped me get through. didn't mean for it to be quite so much for you to read through.
take care of yourself and the baby and enjoy these precious days together. and just remember to drink loads - way more than you think (I would take up 3 pint glasses of squash and get through it in an evening!)