Hi Stomlee,
We are here if you need. I dont know if you're in sydney, but I'm holding a group for young adults with cancer in August and you're welcome to talk to us then.
When it comes to your mum, you dont need to take on anything. Don't feel that you need to look after or prop her up. What is important is just letting her know that she has someone else to talk to (you) when and if she needs.
Also, let her know that you love her. Take on as much as you feel good about, because you love her - not because you have to. As soon as you start to regret helping or looking after her, then you've taken on to much.
I hope that helps.
U can.