Them sacrificing to have you is a copout. THEY made a decision and the result was your birth. After that they had a responsibility and I’m guessing they despised it. Then they took it out on you.

I’m assuming that your sibling was treated better/differently from you and given me opportunities.

Get some counseling and prepare to tell them that either the BS stops or you are moving on without them. This is especially important if you are already out on your own. All healthy relationships are give and take but the biggest key is healthy boundaries, if you set a boundary that abusive communication will to be tolerated and that you are prepared to move on without them they will be shocked and begin trying to argue with you and insult you. At that point walk away without saying a word. Break contact initially for at least a month and after that if they have contacted and seem apologetic make contact again with reinforce your boundary and the consequences.

If they truly care they will make an effort to be decent. If they continue being abusive the odds they are ever going to change is low and you then need to make a decision on whether or not their being in your life is something you want to continue with.

And go out and make some friends. Build a support system that will be there when you need it and understand that you also need to be willing to support them. I broke contact around 2002 and never got help or really made friends. I’m also very bad at dealing with people because of it.