I'm so sorry for your loss dear. It's a terrible feeling when you lose someone. Especially someone who you feel like repaying for all the love they've shown to you. It can be heart breaking. But like you pointed out - you're the next head in line. You're now like a father to your younger ones, and husband to your mother. It's a tough responsibility for a young lady to carry, but I trust that the love only family can bring forth; will give you all the strength and motivation you'll need.