Hi @PookieDo
Sorry you're so run down. It's not surprising though - you are doing so much and it sounds like you have been for so long: raising a family alone, two jobs, no help or support. You really deserve some support.
The good thing is that your DC are teens. They may be needy but they won't die of neglect if you focus on yourself for a couple of weeks.
Can you let them know that you're feeling really unwell (that is easier to understand than worn out or stressed) and you need to take things easy for a bit.
Give yourself a week of R&R as soon as you get home. Pint glass of iced water, iced tea, smoothie or diluted juices and instead of slobbing in front of any old TV, find a box set favourite comedy or a really good feelgood film to watch every night.
Do really simple healthy dinners - do baked potatoes or omlettes, stick a tray of chicken pieces in the oven with some cherry tomatoes and pre chopped veg, with a bag of salad and crusty bread, or buy ready meals. No chopping, prepping but no rubbishy take away fast foods either. Ask DC to wash up, or use paper plates.
For stress, yoga and meditation/affirmations are good. There's loads of free videos online, from 5 mins to full hours. Lots of them have free online courses you can sign up for too. Even if you just do 5 mins a day, that's you doing something beneficial for you.
I find two things make th ebiggest difference to feeling shattered and stressed.
The first is to find tiny ways to squeeze fun or pleasure/treats into the day. Eg - stream your favourite music while you get ready in the morning; watch comedies and favourite films at night, treat yoruself to a face pack, new bubble bath, massage bar etc and use them same day.
The other is to do something - amything, however tiny, every single day, that you've never done before. Walk a new way to work, sing in the shower, wear clothes combinations you've not put together before, order a different drink in a cafe, go to a different cafe. Talk to someone at work you never talk to. Move on from tiny stuff to bigger stuff - apply for a job which has better conditions and a pay rise.
I always bang on about these things but they helped me so much so I hope they help others. I was in a really deep rut - depressed and shattered and doing small stuff like that helped. Along with the usual drink loads of water, eat 8 a day etc.
Really hope you try some of this stuff and that it helps you. 