Hello moms

Kind of a two part question...
My little man just turned 6 weeks old. Recently he's been having trouble sleeping in his crib and I've basically had to get him to sleep in my bed then move him at night but he never stays asleep when put in his crib. The husband and I can't really sleep with him in the bed because there isn't enough room for the three of us to bed share safely at this age. I'm wondering if any other moms have advice on getting LO to sleep and stay asleep in their bed. I usually wait at least 10-15 minutes after he goes to sleep in my arms to put him down since I know he's deep asleep.
Along with this, he's been sleeping 3-6 hour stretches during the day and only 1-2 hour stretches at night. I'm finding myself exhausted during the evenings/nights because of this. I have things to do during the day (cleaning/cooking/errands/etc) just like any other mom and can only put in about an hour or two of nap time myself during the day, if that sometimes. It's like LO has his days/nights mixed again. He was doing great for a while and had days/nights switched well but now it's like we've gone backwards. I'm wondering if I should let him sleep during the day or try to keep him awake or just let it run its course for now. But I'm staying so exhausted at night that at times I have little strength to even hold him and I know that's dangerous. At those times, I just put him in bed beside me and breastfeed lying down for safety and to try and rest while he eats/comforts himself.
Just last week we went through a spell of never sleeping during the day and sleeping 2-3 hour stretches at night, fyi. And my husband can't really help much during the week because of his work schedule (usually up at 6, works 8am-8pm and home around 930pm) so he's always really tired and needs his rest in order to work. And I don't have any family or friends nearby that can really come help and it seems troublesome to ask someone to help during a 2am waking, at least to me.
So any advice on what's going on with LO, how long it will last, and what I can do in the mean time to catch up on sleep and be awake enough when he is to tend his needs would be helpful

Re: 6 week old advice
please don't wake your baby when he is sleeping during the day unless your pediatrician has directed you to in order to provide enough feedings for weight gain. making your baby overtired will not actually result in more sleep at night.
you can try a wedge under the crib mattress to make an incline or using another sleeping vessel like a rock'n'play until LO is older. are you swaddling? swaddling can really help you with your crib sleep quality.
i get that your H needs rest in order to work but i think you should revisit this topic with him. i don't think it is unreasonable for him to help you in the MOTN so that you can get some rest, too, especially if you think you are so tired that it is unsafe. taking care of an infant is work, too, even though you aren't commuting to a desk job.
Met: September 2005 Married: October 2008 DS: 09/2014
As for swaddling they don't really practice that here
And H and I have discussed things because I just was so tired and frustrated. We've worked out some things to try so we shall see how that works out.