Unless your job is your absolute dream job, I’d recommend looking for another one. It sounds like it is taking a lot of your energy and your bosses are probably taking advantage of you. If you’re short staffed now and picking up a lot of the slack there is a decent chance your bosses won’t hire as many people as they need because they’ll expect you to continue to pickup the slack. In the long run this might help your social life by having more time and energy. You also might meet coworkers who become great friends.

Definitely talk to your parents and see if you can cut down on the number of weekends your looking after your brother. You deserve time to yourself too, especially when your parents take off every weekend to have alone time. There needs to be balance.