Im starting to wonder if we made the right decision having 3 kids so close together

I honestly thought I could do it, we already have two less than 15mths apart so whats one more? This pregnancy has been so easy complication-wise, the best of the three so you would think it'd be a breeze. Nope - my hips are killing me, my back aches, the braxton hicks are horrible and I get little to no sleep between a waking toddler (who slept throught until 2 weeks ago ) and constantly needing to pee/move position to get comfy.
Im so sick of yelling at my 2yo for being naughty all the time and having my 1yo hang off my leg like a leech. Im really concerned he isnt going to cope with a new sibling because he is such a mama's boy - and while I like that we are very close I dont want him to be so attached to me that no one else will do. Im worried Dh wont pull his weight after the baby is born when Im going to need some consideration and help to get into a comfortable routine. Im terrified I will give up on breastfeeding because I'll be so exhausted I wont be able to function. I feel like all I do is yell and be cranky and hate my life. I have no family support so Dh is it and I have times where I dearly wish I could just ring my inlaws and say 'Here the boys are yours for the night, enjoy!' They are coming when the baby is born for a few weeks but I dont want to rely on them and then be left floundering when they leave, and Dh cant use his parental leave because Im going to need to use it to go and help my sister when she has her baby (she is alone and Im her only support) in Sydney in July.

Realistically I know in a years time I will look back and think it wasnt so bad but right now, Im very very scared. I thought I could do it, I think I do a pretty decent job being their mum, keeping the house tidy and all that jazz - but maybe I dont and just dont see it

Thanks for letting me get this out.