Been there done that, lived to tell the tale!
You need a plan.
Every day needs a mini plan. Can be just one thing: "Go to the library in the morning", or "do a supermarket shop". Don't be overly ambitious. Just going to the bakery in town, by bus for example, can be an "activity"
You also need back up and support staff.
So get texting all the other mums of kids the same age, get play dates (restrict them to about 2 hrs though), invite people over.
Call any family members and plan a visit.
Ask the GPs/nice aunties to have the kids for an afternoon
Plan regular activities for yourself once DH is home, eg every Wednesday and Friday from 7-9 you are out swimming/running/whatever. This gets written in the diary and is non negotiable.
Let them watch plenty of TV. They'll soon grow out of TV anyway (kids do these days)
Eat what is convenient for you.
Don't just think vaguely: "oh yes, maybe that would work" and then forget, follow my plan to the letter !!!