hello outcast90,
I'm sorry you're having such a rough time and that your Mom is not supportive (quite the opposite). I come from a family where a member was addicted to meds and alcohol - I understand how difficult it is to deal with that alone. But you have to live the life that makes you happy and you have every right to do so! Your mom has no right to put you in such a situation!

Is there any support infrastructure in your country/area that you have access to? Like a hotline or a counceling center? Also, is there anyone else you can confide in? A family member or a friend? Try to find an ally, someone who can support you.
It doesn't sound like it, but if there is any chance at all you could speak to your dad again, without your mother being present, then do that! Your mother suffers, and she needs help, but you need to look after yourself too.
Take care!