Am I being selfish?

I understand how you feel. It is too heavy a burden for you to take care of all them financially. If you feel like leaving them without financial support, I don't think that is selfishness. Your parents and other relatives should understand that you have other responsibilities other than them. You have a child. They should work for themselves, too, and not rely on you for financial support. It is ok to help a little but not all the time. Besides, as you said, your brother is married. He should be the one providing for his family not you. It is too much for you to support all of them financially. "Give man a fish and he will ask from you forever. Teach a man to fish and he will take care of himself." Well, I couldn't quote the exact words of Jesus in the bible but it's something like this. Let your family members realize that they also have to take part in the responsibility and not rely on you always. Anyone who has a situation like you will want to be out and be relieved of the burden. It's just too much, I think.

I don't think you are being selfish at all. You earn your money and can do whatever you want with it. I would tell my brother to get off his butt and find a job. Stop supporting his habits. I also think your mom was just trying to make sure you have all of your bases covered. Do what makes you happy. If you are happy then your daughter will be too.