Really regretting taking a gap year. Can I change my mind?

Hi there, I'm really regretting my decision to take a gap year...

I was so sure I wanted to take a gap year at the star of the academic year that I didn't even apply for deferred entry (for my school UCAS deadline was 1st October). I've only been on summer holiday for a month and I'm already feeling a bit isolated and depressed. I come from a school were most of the students and my friends are boarders who live in various different countries but I have 5 good friends who were also day pupils, nevertheless between us we live 3 hours away so only meet up about once a fortnight.

When I'm not with my friends I just feel really miserable, feelings made worse when I think about the fact that they are all going to university next year whilst I'm not. I've applied for many jobs to try and keep me busy but with no luck as of yet. I just can't imagine doing this for a whole year especially if I'm not going to have any friends nearby. As well as this, without trying to sound stuck up, I'm more mature than the majority of my age group and really don't want to go to university with people younger than me.

To make matters worse I'm terrified for results day because I know I have let myself down. I missed a 10 marker out on a psychology paper and I completely misinterpreted a 15 and 25 mark question in economics. So I don't even know if I can ever go to university.

So essentially with all this in mind I have two questions:

1) Is taking a gap year all that bad?
Or
2) Is there anyway I can apply for a course starting in September?

Thanks for any advice.

Is taking a gap year all that bad?