Help! I need help mothering orphaned kittens!

So I know this isn’t glow material usually but I need help. I just took in two orphan kitties two days ago. They haven’t opened their eyes so I’m guessing they are about 5-6 days old. Anyway they are eating great and all but they just won’t stop crying.. I help them urinate every time I feed them but they have not pooped since the night I got them and I’m kind of worried. Also they willl just not stop meowing even after feedings .. it feels like they want to eat round the clock. They are taking down about 5 tablespoons of milk a day but idk their constant meowing makes me feel like there’s something wrong. Does anyone have any advise? They are babies and I just feel helpless

Update : Thanks girlies for all your support and stuff lol soo a lot of you asked what milk I was feeding them and I have been feeding them kitten milk replacer from

The very beginning so don’t you worry about that. I estimate the are about 6-7 days old because one of them just about opened his eyes. I have a boy and a girl and they are doing much better now.. both have pooped so no need to worry about that now, I think it was just the change from mother’s milk to formula that caused them the trouble. But they are okay. They are getting a little chunky now which I love because I know they are healthy. I will try the cuddling thing now but haven’t before because I thought the hot water bottles I provided form them to be enough. They are crying less now and sleeping a whole lot more compared to when I first got them. They are eating more and sleeping more. So I think that’s a good sign. Still haven’t thought of names tho. But I have been putting a little purring sound on for them and they find it very comforting. :) thanks everyone