Squirl, don't give up on the pack yet. Please take the advice of really experienced and knowledgable people on here and have a trainer come out to observe and educate you, so you can train and keep them all.
I have three dogs right now. A 13 year old Corgi mix and two 6 month old Papillons. Boy, are these pups a handful! They are cute as all get out, but regardless of how much exercise and entertainment they get, I have NEVER been able to exhaust them!! LOL
I just got back from 6 months in Florida and as I left, I picked up the 5 month old kitty the vet who befriended me there had kept for me. The Paps are chasing this cat from the time they all wake up, til the time they all go to bed!!! If they aren't chasing him, then the kitty is chasing them. OMG. The cacophony all day long is exhausting, but I wouldn't change a thing. It will all work out. They all love each other. Even my 6 year old cat is now quickly accepting the kitty. That's pretty amazing.
They do exhaust me on some days and I imagine having the kitten in the mix will add to it in the near term, but the payoff from having loving, hilarious furbabies in your life everyday is just..... SO worth it!!!
Please try the trainer and maybe you could get someone to give you a respite for an afternoon so you can get some time off from the house? That might help your mindset as well.
Hang in there!!!