My I say in the gentlest possible way you are looking in the wrong direction? It is 2 years since your little girl's dad died in horrible circumstances and I'm assuming he meant a lot to you. If not my apologies for the assumption however the below still holds true.
So now you have your own grief and loss to contend with as well as a little girl that needs constant help and looks to you for it all. Plus the practical aspects of living, chores, shopping and all
How do you expect to cope wiht all of that just becuse you are a mum. You are human, you get tired, frustrated, angry and resentful -and want a break. OK that's natural and does not indicate a lack of love or being a bad parent - just being human who, like every other in the world has limits.
May I ask if you have considered a child psychologist for your little daughter and a grief councilor or psychologist for yourself? You both have gone through something nobody aught to, and both of you need knowledgeable support.
Apart from that may I ask if you are facing all this alone, or have others to lean on? Maybe someone to babysit, maybe someone just to talk frankly with and hear care in their voice as they listen?
Being alone can lead you down the path of self blame as there is no one to provide perspective -and a measure of comfort.
To survive for two years with these burdens shows love and strenght, please don't put yourself down
You are welcome here -to say whatever you like - anytime