My mum just lashes out at me for literally no reason ?

Instead of asking us, why don't you tell her how you feel and ask your mom if everything is alright with her? Maybe something is going on in her life that she hasn't let on and every little thing bothers her. A letter always helps, cuz sometimes you can put things better into words when you write it down. Give it a go and see if that doesn't get down to the root of the problem.