Hi and welcome to Beyond Blue. As your nick name says, "This too shall pass" but it will take time, how much, only you will know.
It sounds like you really loved this guy and his daughters, and put a lot of time and effort into your relationship and also into helping your guy with his depression.
Depression is a hard illness to live with, and when it flares up, people sometimes behave differently and unexpectedly.
I'm wondering if you are going through a grief period, which would be totally possible after the loss of not just your boyfriend, his girls, but the sense of family. I suggest you Google grief and look at the different steps involved.
It is great you have returned to some of your normal events and are catching up with friends. All of those things are important, so you are taking the right steps to return to some form of normalcy for you.
Regarding the house, start with one room at a time. Maybe your bedroom, then the kitchen, or the other way around. Take small steps, one job at a time.
You could use the Beyond Blue phone number or chat line for help and advice on how to cope and get back on your feet.
Like I mentioned, check out the stages of grief and see if any of that fits for you.
Thinking of you, from Mrs. Dools