Hi Sadie,
So sorry to read your post and to know that you are unable to talk with family or friends about how you are feeling. If you think it would help please contact us at Icarus trust. We are a charity that offers support to people in your situation, having to deal with addiction in the family. We have trained and experienced people called family friends who you could talk with if you get in touch. They are good listeners and would understand how you are feeling so maybe talking with one of them might help you to know what to do next.
You can contact Icarus Trust on help@icarustrust.org or visit our website http://www.icarustrust.org
All the best to you.