Oh crikey, it will definitely get better. I put off my mother coming straight after my c-sec because I knew space would be more important than help to me. Not that that's much help to you now.
Can you send them out for an afternoon, after getting them to make sure you are well stocked up with drinks and snacks?
What you need is peace and quiet and lots of time with your baby. I know from my experience that it is near impossible to feel comfortable BF a new baby around people who are disapproving. My mother came after a week and kept telling me to give him a bottle to "give myself a break" and questioning why I fed so often, which made me want to hold off feeding him, which is absolutely not what you need.
Take the baby up to bed with you and stay there, or if you would rather commandeer the living room do that, it's your house. But wherever you are, they need to know that they don't hang around you all day making you feel uncomfortable, they should be leaving the room, not you. If he's on the breast all bloody day, the more the better. At that age my DS rarely went for more than half an hour break before having another feed, which makes sense as BM takes 20 minutes to digest, so he was just keeping himself full.
Keep feeding him lots. I'm not sure about the pump and top ups? Are you expressing then giving him the EBM? this seems really silly as the baby will get more milk out of you if his latch is ok (and if it's not, then that is the problem to resolve) and will better stimulate your supply. If the top up is formula, then it won't be helping your supply, he needs to feed and feed and feed, from you, not have formula sitting on his tummy making him too full to eat more! I would discuss this with a MW (maybe a different one to the first) and/or a BFC, to make sure you are doing the best thing. If you want to monitor his intake you can always weigh him before and after feeds. If you question their advice they will either validate it for your peace of mind, or it will become clear the advice is flawed. Are you tickling his cheek/feet to keep him awake when feeding (pretending to pull the nipple away from him can stimulate more sucking too). Have you tried breast compression to get him sucking faster when he slows down? Have you tried changing his nappy to wake him up to feed him some more?
The idea that BM doesn't put weight on babies is rubbish. DS was putting on a pound a week for his first 6 weeks (after initial loss yadda yadda), he started off at 7lbs2 (bang on average) and he's HUGE now, 12 weeks and growing out of 3-6 month clothes.
It will get so, so much better. Houseguests with a new baby are never much fun, no matter how helpful they are I know I can never relax properly. A couple of hours a day to help with your laundry, cook you a meal or whatever is much better, I would get DH to chat to them about going out for stretches during the day, or just leaving you alone in your nest of choice while they do the garden, clean the rest of the house, walk the dog or whatever.
Feeding will get easy. Static weight is still not loss, and if you stick with it, in a couple of weeks it will be lovely.