Can't see light at the end of the tunnel. What do I do?

I'm a gay in the closet (only one of my best friends knows) and I'm really struggling with accepting my sexuality due to external factors.Firstly, my family (including my close and wider) is quite homophobic. My Mum is always making offensive comments about LGBT people and she doesn't realise how offensive she really is. My Dad is stays quiet when my Mum makes these comments, but he never condemns and has said stuff on his own accord in the past about how being gay is mainly choice and nurture. I also have a brother (he's 20) who is extremely homophobic and I already don't get on with him at all whatsoever so if I ever did come out I feel he would persecute me for it.As well as this, my wider family such as my grandparents are awfully homophobic. For example, on Christmas Day my whole family got together and they spent an hour ranting about "poofs" and how there were too many LGBT people on TV and just making offensive remarks and jokes.Quite simply, because of growing up with this influence (I'm 18 and have known since I was 16), I am unable to fully accept who I am. I feel almost guilty for being gay and if I have thoughts or feeling about guys I just feel repulsed in myself for having those feelings. I'm just so worried for what the future holds because I'm never going to be able to get into a relationship or anything with a mindset like this and with a family I don't feel would be very supportive.The only upside is that I'll be moving out soon to a city a bit away to start my career and live on my own. I just don't know if I'll ever be able to come out to my family? I really would appreciate people to speak to about this and some advice as my head is all over the place at the moment.