Needing to Scream!

Well where do i start to begin. Its been a while since i have been on here. Almost a year. And i think to myself why havent  I came on here sooner. There are ppl on here that are going through the same thing or similar. Why do i feel like i can spill my guts to ppl I dont know, and not to the closest ppl around me.I have such a clever way of putting on that fake smile when its needed, and my friends just dont understand. I always here about there problems and they never take the time to hear me. So there i go again, just all those bottled up emotions go down..down into the bottom and are never brought up. Im just afraid 1 day im just going to lose it, and do something that iam going to regret.Why i'm needing to scream. Well it has been a crazy, stressul, lonely, depressed time.I found out about 5 mths ago, that my mother was diagnosed with cancer, so hard, i practically cried everyday until there was no more tears coming out. After trying to deal with that stress my sister had twins, and im the one to get lean on to help her with the babies. I mean dont get me wrong i love m sister and those babies, but should i be dealing with the stress of looking after a 5 month old. Im 21 years old i should not be worrying about a child. The question i always ask myself is "when did i become a mom"?I know this sounds horrible, i think it sounds bad. But i never had anytime for myself to just..be at peace. Its always me who has to be the strong one, the one who has it all together. I dont get it. I dont get me. How am i suppose to live my life if i keep on getting pulled back down?