Im student lone parent too.
You must absolutly get them sleeping without you laying with them a routine of an afternoon/evening after school is a must. Childrens snack, home work, reading before the T.V goes on or out to play. dinner and then kids help with kitchen and tidying and then baths etc with a fairly ridgid bed time. I always turn the T.V off and set my learning books, word document etc up prior to taking them to bed, so I am ready to go, without being distracted by tv cleaning etc.
My dd was similar with sleeping, but It was getting too much so I told her she was too big for this and was just pretty strong willed with her. I told her if she did not make a fuss I would be in to see her in 5 mins, then 10 mins then 15, then 20, 25 etc untill she was sleep. If she was quite and well behaved I went in if she was not I would not, so she would call from the top of the stairs etc and I would just go to the bottom and reasure her that I would be up if she settled well. It really did work and she settled self by the end of one week. Even now she says ill see you in 5 mins and I put her to bed, even though I dont often check her before she is asleep.
My dd also struggles to sleep some times and so I do let her have books, magazines a few small toys in bed and she reads, makes displays
and all sorts, so long as she is quiet and calm and winding down I leave her to as she pleases. she is often still awake chuntering and playing untill gone 10pm. It is impossible to physically force a child to sleep.
There are times especially near to deadlines where things are disorganised and far from perfect in my house, but that is the way it goes. so long as basics are taken care of then untidyness sometimes needs to be tolerated.
It is important to plan ahead, I go back in 2 weeks so Iam now getting my house in order ready to start with a clean and tidy house. I have had a massive de clutter and deep clean. I know by the end of my 3rd week things will be stepping up and I will be working towards deadlines so I need to be able to focus on this and keep on top things like washing daily tidying and cleaning the bathroom etc.
I split my study days into cleaning and tidying and then working and my uni days I make sure the house is in order before going to bed so at least I will then come home to clean house if breakfast things can just get rinsed out and everyopne out the door on time.
It is stressfull, more so than when I was working and also as dd gets older it is more demanding too as we need to accomodate her activities. You need to be able to account for evry making moment you have.