My DD is a but older, but have been on my own since the start, so know how it feels. Also a CM so up to 6 kids during day, and DD doesnt sleep, so exhausted pretty often!)
Think the best thing to do first is take a day off. Take the kids out and have a really fun time, and relax. DO NOT think about what needs done, just enjoy the moment.
Then, the next morning start a list of exactly what needs done in very small steps, and then decide what is the highest priority. Also make a list of anyone you know who is "handy" who might be able to help out, even for an hour, and call them. If you arent happy with him taking them out, can your xp sit with them while they have a bath? That has always distracted and calmed my dd well, and she would happily stay there for hours!
Or, can you make them part of the project? Using building beds as an example, can the kids jump on the mattress while you build the bed? Make a fort with bedding? Are they old enough to "help"? My DD is 6 and can now build beds single handedly - I do the heavy lifting, she screws the bits in...she also put the living room coffee table and bookcase together while I did an assignment on the pc in same room
Alternatively, make a huge deal of going to the library to pick a special DVD or two. It will not hurt the kids to watch TV for an hour or two a day for a week... Once house is sorted you will be so much more relaxed and ready to play, they will forget about watching it!
Again, will depend on their age, but if you have a timer, can you say, right, im gonna do this job for 10 mins. As soon as the buzzer goes we will have a drink and a snack / play hide and seek for two hides etc etc
Take a decent break during the day - even a trip to B&Q followed by 20 mins in the park...
Then, once they go to bed, get yourself ready for bed too and chill out. Have a cup of tea and remind yourself what you have accomplished that day / tick off things on to-do list! If you dont rest at night, how on earth will you have energy during the day!