Should I tell someone how I feel?

[Sasha]

So I am extremely depressed at the moment, I live with an abusive mother who beat me as a child amongst many, many other things which have gone wrong in my life during the past few years, I can't trust anyone in my family except my grandmother, and I feel so much biterness and hate from the rest of them. I'm suicidal and have been for a while. Pretty much everyday the thought of it runs through my mind. It's not that I actually really want to die, it's just I feel like I can't go on living, everything is just too hard and too difficult and too painful. I'm 19 years old. I have been self harming for the past few years too. I never talk about it with anyone. My mum is a very cruel and manipulative person, let's just leave it at that.
Should I speak to my grandmother about how I feel. I feel like no one cares though, like no one can empathize and everyone thinks 'tough love' is the way to go, which only makes me feel worse and doesn't work on me at all. I'm extremely sensitive at the moment and the tiniest of things really get to me. I hate how people are so unsympathetic towards depression and they act like you've decided to be depressed and as though you can switch it off if you wanted but it's impossible.
Would speaking about it to my grandmother help?? I don't know what to do anymore as I've really run out of options. I feel deserted and abandoned. Like everyone is turning their back on me because I'm depressed. Everyone loves you when you're happy and everything is going well for you, when you're healthy and you look your best and stuff, but once things start going down hill for you they desert you faster than a flash. I feel like talking about my feeling might be seen as weakness to her. Most of my family are very un-understanding people, and very unempathetic towards others, especially when it comes to mental ilness. My gran isn't like that, but still. I just feel like truely, no one cares on the face on the earth. I feel trapped in my life and my situation, like there's no way out. I feel mentally and emotionally manipulated by my mum, and I feel helpless.