I Feel Really Mentally Unstable.

So, where do I begin?
In truth, I’ve suffered from on/off depression for 4 years now.
For the majority of this time my self-esteem has been rock bottom, I’ve had no self-confidence, no self-belief, no feeling of self-worth and really just wanted to die. In the past I have on several occasions attempted to, or contemplated attempting to commit suicide. For a long time I wasn’t able to look at a knife without wanting to stab myself, or a bottle of bleach without wanting to drink it. I used to go to sleep wishing I wouldn’t wake up the next morning. In hindsight, the only thing I can credit my still being alive to is a total lack of guts back when I was suicidally depressed.
But that’s all in the past now. I may still be depressed, but at least I’m over the suicidally bit.

Right now though, I seem to be really emotionally unstable. I get upset or angry over the most minor and pathetic of things - for instance, just last week I almost broke down in tears when I was making my bed and couldn’t get it how I wanted it to look. It sounds ridiculous I know, but this is what’s happening to me at the moment.
To be honest, all I really want is to come out, but with a total lack of confidence that seems to burdening me day in day out, I don’t know that I’ll ever have the courage to do this.
For about two years at school I was bullied, and during that time I felt like I had what little self-esteem and self-confidence I actually had beaten out of me. As a result of this I became socially inept and emotionally detached and suffice to say, I’ve now become completely introverted and have trouble opening up to people (even those I’m closest to). Whilst the aforementioned bullying was 2/3 years ago and is no longer a problem, (and I now have a good group of close friends), the above are still issues, that is, a lack of self-esteem/confidence, social ineptness and being emotionally detached and unable to open up.
Moreover, I feel like the people I’m around every day prohibit me from coming out. A Muslim father; a mother who tells me that I’m her only hope of her having grandchildren; a homophobic brother who has on more than one occasion told me that Gays should be shot; deeply Christian relatives and a sixth form largely full of chauvinistic, self-righteous students. Being around such people make me feel like I have to suppress who I am and act homophobic to simply fit in, and as much as I hate to say it, it makes me ashamed of being gay.

For me though, the scariest thing is that these suppressed emotions manifest as hatred of everyone else. I don’t know why – I’m not a violent or vindictive person, but lately I’ve been getting short-tempered and spiteful to people unnecessarily. Particularly my mum – I will get really angry at her over nothing and will become really vindictive. Sometimes all she has to do is look at me in a way which I think is weird or say something in a strange voice and I’ll get angry and start making malicious comments under my breath, or in other situations, I’ll have thoughts of physically hurting someone going through my head. I don’t know why this is. As I said, I’m not a violent person – I’ve never intentionally hurt someone and hope that I never would but I’m really scared that I’m going to and I hate myself for this. I don’t know what to do.

So having just established I have no self-esteem and can’t open up to people, I’m sure you can imagine how difficult it is for me to ask someone for help. It’s taken me long enough to conjure up the courage to write something on here, and this is directed to a group of people who I’ll likely never see face to face in my entire life. As such, I don’t see that I’d ever be able to talk to a psychologist about the above issues and am really lost for what to do.
I know I’m depressed, suffering from emotional instability and a lack of self-esteem, but I just don’t know how to deal with it.
Any advice would be much appreciated.