Angel,
I know exactly what you're going through. I was there at 19, in a situation very similar to yours. I'm 27 now and I'm getting ready to spread my wings again for the first time since my divorce when I was 21. I have a very controlling family. They demand that I follow their advice. If I don't, they get mad.
I plan to get a new job and go back to school full-time to finish my degree at Uni.
I didn't know about these products for D/HH individuals until I came here in 2006. Now, I am actively seeking ways to get these products for when I move out in the future (hopefully soon as I'm on a waiting list for income-based housing).
You're 19 and old enough to be responsible for you. You need to sit down with your sister and the rest of your family and explain to them that you are HoH, and give them examples of what you can and cannot hear as well as easy accommodations that will be helpful not just for you, but for everyone because then communication is improved and tempers will flare less often. Tell them that you prefer to text rather than receive voice calls, remind them of this constantly. Don't call them, text them only or email them. They will eventually get the idea. Heck they might learn that even they might prefer to text too. Also, if there are ways out there to receive a phone flasher/door flasher/smoke alarm flasher, I would find ways to get these installed.
I grew up with everyone telling me what my needs were and my input wasn't ever heard. Well now I'm the one telling others what my needs are and their input is heard but isn't always followed.
I wouldn't call this bravery, but I've noticed that with the right friends and the right surroundings, your self-esteem will start to get a boost to where you will begin to believe in yourself again.
A year ago I was afraid to move out, afraid that I was going to fail. Well now, I've gotten a boost in the self-confidence department.
Believe me there are several people here that have been in your shoes here and they are here to support you, including myself.
Hang in there Angel, your wings are going to spread and take flight soon!