I don’t know what else to do..suicidal for years

Hi everyone.
I’m beautiful and 40, a mother, creative, playful and wonderful.
Yet I’ve struggled with suicidal thoughts and attempts since I was 14/15 years old.
I’m struggling so bad right now.
I am sick with lung disease and waiting results. I may only have a few years left but won’t know for a couple of months.
But still I struggle, every week with being here on this earth with people who are cruel and wonder what purpose does human life have here.
As a mum it’s so hard because I don’t want to leave my girls, but I don’t know what else to do, how to feel, how to be ok with feeling so much pain every day.
Most people would look at me and think I’m happy and beautiful and a great mum…but inside I’m screaming with pain. I hide it soooooo well.
There’s a part of me that is hoping I’m dying and knows what I’d do with those last few years. Then there’s a part of me that wants to live but has no idea how to manage 30 years of life.
25 years of pain is soooooo long. I don’t get how some struggle like me and have what I have and others have nothing and never think of dying.
I don’t get it. I’ve prayed and prayed.
I don’t know what to do.
There are days I drive to places to end my life in beautiful nature and then I dont. There are days I slash my wrists and say it’s from gardening and barely bleed.
There are days I hold fire on my body and then blame the oven.
I don’t know why I feel like this for so many years..I just don’t understand. Why????