Maybell, I can certainly relate and understand your struggle. I've been doing it since my D9 was an infant. But I have only had one kid, and boy, do I give you props for making it work with 3!!!
My journey hasn't been an easy one, and I haven't gotten much help except from paid sources. I've had quite a few different jobs within my profession to try to make this work.
I currently work full-time, I am back in school, I attend the gym, have a new boyfriend, and of course care for my D9. Some days it falls apart. Other days it just works. My work has been suffering a little lately, but I have to get it back on track. Prioritizing is key. I don't think we could be superwoman at everything we try to tackle, but we can only do the best we can.
One thing that has really helped me is having my D9 take a decent amount of responsibility. I explained to her I need her help and I need her to be a team with me. I do not check to make sure her HW is done. I ask, if she says yes, I take her word for it. She knows I will find out if it isn't, and there will be consequences. Of course I help her where it is needed. She does her own laundry. She packs her own lunchbox every morning. They sound like small things, but they help me tremendously.
Career wise, I make decent money, my job is pretty easy, but it's not where I want to be professionally right now. But I understand it is a sacrifice I need to make right now. Something always has to give. My career gives right now.
I have once a month cleaning service. It's worth the money. I build my schedule around my exercise. I meal prep so there is always something to eat. I buy when I need to.
As far as the BF goes, he is great. We do spend a lot of time together, and I try to work that in. I let him help me. I let him do HW with D9 if he happens to be over.
My friends have been slightly on the backburner. Luckily they are lifelong friends who understand I am just trying to figure out how to make things work with a new addition into my life amongst all the other chaos.
My point is that sometimes certain things need ot take a back seat to others. And those things will change positions often. It's a lot of trial and error and it's a lot of accepting things won't be perfect.
Find yourself help wherever you can. The little things add up.
You are doing great. You are horrible at nothing. You got this.