No one realise how difficult it is to be entirely responsible for two boys with literally no help.
I know I’m no use to you IRL but i just want to tell you I do. I have two boys, entirely on my own, no dad at all, no partner, youngest has SEN, had the violence for far too long, Social services, police, you name it. Unlike you I couldn’t even complete my degree because it was just all too much (fucking well done to you! That’s a proper achievement. You’ve a brain in your head and a work ethic to get you places) I felt like a piece of shit. I was a useless mother. Failing them both. It was hell. I know how you’re feeling. I also know that it will get better. With some grit and determination on your part, you will turn out a couple of fine young men that have you bursting with pride. 
DS1 has some learning difficulties, EP thinks possibly ASD
Are you seeking an assessment? It can be really helpful for your DS as they can use a diagnosis to put proper support in place for him in school.
will follow the advice given and I know it's not going to be an overnight fix
No it really won’t. It will be small steps, every day and one day you will be getting ready for bed and you’ll realise no-one shouted at anyone today.
Not sure what is available in your area but Action for children were good with my DC. Also play therapy for the youngest (massive anger issues) social services paid for it. I was extremely lucky to get an amazing social worker. Do you have a local children’s centre? You could ask for support. Or even ask your GP if they can suggest any services.