Why did Heavenly Father Trust me with them?

As a mom of special needs kids I wonder often why he trusts me with them. I have been told that I had these kids for a reason and that heavenly father has blessed me with them. That he knows I can take care of them and teach them and help them grow.

But its beyond hard. My daughter was diagnosed with FASD this last year. I drank under 6 drinks in the first 6 weeks of my twin pregnancy. My ex also drank quite a bit and they think his factor of drinking helped too. My Son who is the other twin has other issues but it looks like he has FASD as well.

With this I have to tell them things in one step. They dont have the memory skills to do things that take more then two steps. They still at age 8 forget to wipe there bum and flush the toilet and wash there hands. If i dont tell them what type of clothing to wear they will wear long sleved clothing and long johns in the summer and scooter shorts and tanks tops in the winter.

Then if i sleep in they will eat all the snacks for breakfast. Like this last week I had some extra money and went shopping and they ate 2 weeks of groceries in 3 days. Hiding wrappers and garbage till the flys come out and I find out.

My youngest is starting to show issues. I left my kids father due to abuse. When he hurt one of the kids I took them and left. He hit and shook the youngest. I thought she had gotten off scott free but recently she has been hording food in her room and not sleeping and lots of other things. Im exhausted. I really am.

I have no family that will take them. There grandparents on there fathers side refuses to help me. There grandfather on the dads side thinks im a gold digging bi**h because Im asking for help with day care so I can get out of poverty.

Currently I have less income then welfare. I have to raise 3 children with special needs and myself on less money then welfare. I have spent all the money I was given as inheritance on court costs and thing the kids needed like medication, food ect.

I dont know where this is going. I Just know I feel lost. I feel hurt. I feel like Heavenly Father has too much faith in me. I dont know if I will ever be able to take care of these kids.

I feel lost and hurt a lot of the time. Being a single parent is hard. Being a single parent to special needs kids is harder.

some times I feel like I have messed my life up. Not saying my kids are a wrong decisision. But that I just dont do right things. That I have screwed things up. That I will never be any good.
I mean what guy in there right mind would want to take on someone like me, and my three messed up children. We are not worth it.