Is there anything to settle my mum with dementia at night? I'm about to have a breakdown.

looking after my mum with dementia, 24/7, is causing severe depression and I also have ptsd through a robbery on my dads home were I and my dad were nearly killed, my dad is also ill ptsd and depression and needs a hip replacement suffering severe pain and can hardly walk, so im looking after both, I get no sleep of a night what so ever im up and down the stairs all night as I put my mum to bed she gets up all the time, I put her back to bed and shes up again, this carries on till about 7 in the morning while im following her sobbing and exhausted, I tried all tablets but they don't work, she fights it, then I out her on nytol bingo, it worked for so long now the effect has worn of, she is on the go all day and all night and will nod of for an hour or so in the day, surly to god there's got to be something out there, I genuinely feel as if im having a breakdown but cant fully because there's no way I would put my mum in care, I will carry on till I drop, she needs to go into respite care just the days only, but she wont go and I no she will be looking for me and crying, I don't no what to do maybe it wouldn't be so bad if she had a normal sleep pattern, you wouldn't let a dog suffer in this way never mind a human being alzimers and dementia are horrible cruel life destroying illnesses I feel for for you all who care for your loved ones, don't no how much longer I can cope this is cruel so cruel