I know that puppies are bouncy, but she does not listen at all. She jumps up incessantly and it isn't getting any better. She responds to "sit" and to "down" but that's mostly on her own terms.
It's not that she's not listening to you, it's that she doesn't understand what you're asking of her. You need to teach commands and reinforce them hundreds of times before a dog can "know" them. If you don't know how to train her, then you either need to get a trainer in, or take her to puppy classes. You could also try YouTube - KikoPup is really good at teaching basic obedience commands and tricks.
She's also very destructive and has ruined my kitchen flooring as well as my sofa.
Management is key here. If she's destructive, stop leaving her alone to be destructive. Crate training would be a good idea for a young puppy, or you could get a pen so that she has a bit more space to move around, but can't escape and destroy your house. Baby gates are also a good way of managing the dogs' space.
She wees and poos in the house constantly, 5+ times per day. She knows that outside is for the toilet as she often will go in the garden and go for a wee straight away. She did a wee on the sofa yesterday, right in front of me.
You need to go back to basics. Take her outside every thirty minutes while she's awake, as well as after sleep, play, eating, drinking and training. You need to go out with her (ideally pop her on a lead) and stay out there until she's been to the toilet. Then, lots of praise, fuss and a nice high value treat to encourage to her to go outside again. Accidents need to be ignored and cleaned up with a proper pet enzyme cleaner.
She is well walked/exercised and has toys and bones to chew on.
How much are you walking her? Young puppies don't need huge amounts of exercise - at 5 months, half an hour twice a day should be absolutely plenty for her. If you're doing too much more than that, she could be over stimulated and unable to calm herself down. I would try two walks a day, then encourage her to nap after each walk so she calms down.
I feel bad and want to give her a loving home but she is driving me insane. Am I being to hard on her/expecting too much? I can't afford to keep replacing things and can't carry on having a house that stinks.
Puppies are hard work and if she came from a poor environment, she may not have been well socialised or trained, which makes things even harder. You'll need to put a lot of work in but at 5 months she's certainly not a lost cause. Persistence is key.