Be kind to yourself - doing the work of two is tough.
A layer of dust is not the end of the world.
Batch cooking, slow cooker, sandwiches, picky bits.... are all your friends.
Once you have a routine that works, go with it. There were evenings I would rebel and not make the packed unches or not put the.washing on and then regret it the next day. It is drudgery but it's there for a reason!
They can do a bowl of cereal from very young. They can also dress themselves, bring down washing baskets, put things in the dishwasher, peg out washing (always good for a laugh!) and make a simple sandwich and toast.
I have a £2 jar. Any £2 coins I get are saved in it. The stipulation for the £2 jar is that the money must be spent on me and it must buy something I absolutely do not need (spa day, another handbag....). My kids knew to keep £2 coins for me and that I would always swap them.
All holidays are fun. Caravans, tents, cottages or trailing everyone through an airport at 4am. Do what is within budget but don't let being alone stop you. There are single parent holidays if you really can't face doing it alone (but an expensive option).
Internet supermarket shopping is a god send.