Poor you OP. I was a single parent with no family support nearby so I can totally empathise, I was much the same as you although I only had the one kid!
Let the kids watch TV all morning if they want to. Don't fret about too much TV / screens / whatever. Survival is key at this point.
Occasionally I would drop my kid at my mum's for the weekend (a few hours away) and then come home and just cry for half an hour due to the sheer overwhelm hitting me.
When they start nursery or school it will be a lot easier. Although in some ways the only way out is "through" with little ones. So there will be some tough times but it does get easier.
Another thing I found was to "go with the flow" helps a lot. Don't panic if you're not being a perfect parent, it's nigh on impossible when you have very small children. Just getting through the day is enough! Bribes, TV, snacks all ok! When they are a bit older you can revert to other methods.
Go to bed when the kids do once or twice a week, the early night will help you to reset and feel a bit more normal. I used to fight and try to get my alone time in the evenings but it led to sheer exhaustion which was worse!!
Make sure you leave the house with them at least once a day. A walk can do you all wonders especially if things are getting fraught.
Best of luck Op, make sure to get one or two things in the diary for you - a swim and sauna or something, anything that's a break from home with something relaxing to do. xx