help on university and advice please.?

I am an undergraduate student studying Economics and Applied Mathematics. It's my first year and I'm finding every subject difficult. I am trying my best to understand all that I can. It's the fourth week and I already feel like quitting. I am studying day and night but when it comes to answering questions I am completely confused. The questions seem like they're from some other subject. I am at breaking point and feel I am going to fail. I have no background in Economics so this is all new to me. Sorry to sound like such a moan but I'm really feeling low. Is first year the most difficult? The maths is solid. I try to do one subject then i fall behind on the other. Serious help and guidance needed please