Wow!  My first impression is you both, parents and you, need space.  They need their privacy as much as you do.  If at all possible designate an area of the house as theres.  You cant enter there unless you knock, unless they invite you in.  Same for you, a private space.  Hire or beg someone to take them out one day or evening to do something they like to do.  That will give you a night to vent and be alone.  I have taken care of my parents the last 5 years.  My want to help them, I have bulldosed them at times.  I need to step back, breath and talk to them.  Dad knows what she needs and what problems she is having, pick his brain.  Ask his opinion, ask her opinion as to how to make things easier.  Family meetings once a week are not a bad idea.  My younger sister lived with I and my husband for a couple of years.  We would get frustrated with her, and didn’t realize how we were annoying her.  Give them jobs,  we as humans feel useless, get depressed if we have no purpose.  My mother has pretty severe dementia, my sister visited day before she doesn’t remember.  Misses medications, can’t do a recipe , wanders can’t remember why she is there.  But she was always a big cook, baker.  So I buy prepared crusts, premeasure items for fruit.  Then she makes a pie, and we all make sure we tell her how delicious it is.   Dad needs the same thing, needs to know he is important, still a bread winner.  Best of Luck.  Remember we love them.