I'm a 19 year old female, I just went to college so I've pretty much left my house and I live in a completely different country than my parents. Ever since i turned 16 my mum feels more and more comfortable in confining in me which I'm so happy about and grateful. However, everyone in the family now dumps everything on me, while I'm away at college making it difficult to study and when I'm back home for the holidays. My mum dumps all her issues on me, how she's physically tired and can't clean the house everyday anymore so I make sure that I do all the washing, cleaning whenever I can to try and reduce the load but it never seems to get better.. Other issues between here and my father, if they argue I know and I try to give the best advice. If anything in the house breaks, malfunctions my mum stresses out and takes it out on me. This goes for my father too with all his issues as well as my younger brother (17 yr old) who I dedicate alot of my time helping him out with his IB assignments at school and proof reading his essays. To you I might sound like I'm ungrateful or I'm not trying to give back. I happily do it but I've reached a point where I feel helpless and tired of it all. I can only take so much and on top of that I also have my life and my problems like every normal human being does. Just imagine having to deal with all your stuff + 3 other family members who's well-being affects yours + college work + friends (the usual). I feel so helpless.. Ever since last year the thought of suicide has come to mind but I'm always like I'd never do that, it would devastate all those who love me and I'd be selfish but now I worry for my own health.. I don't know what to do anymore. I've become so emotional, bursting out in tears at night and not being able to sleep. I just don't know anymore.

Tell your mum when she is burdening you with her problems, maybe ask her to write them down for you so she still gets to vent but you can skim them at your own pace.
It's good to be helpful but you can't help if your burned out.
Maybe next break you could take a holiday.
Your parents should not be using you as a buddy they can vent to, to relieve the burden of their arguments. If they start to talk about it again with you, tell them it makes you feel uncomfortable and you don't want to have that conversation with them. Keep telling them until they stop or leave the room if you have to. They should know better. You are their child and no matter how old you get, you are not there to give them advice on how to live their lives happily.
Unless you actually still live at home, stop doing your mum's cleaning for her while you're in school. It's just an extra responsibility that you don't need while you're focusing on your school-work. It doesn't matter if she is unable to cope with it, it's her house and she needs to take responsibility for it.
As for your brother and helping him with school; proof-reading is not something you should help him with all of the time. He needs to learn to proof-read his own assignments because that is what will be expected of him in college, and life for that matter.
[You should change the title of your story because it doesn't seem to relate to your story. I thought this was going to be about murder, not a stressful home-life.]