Who do you turn to when you're stuck? Who are your readers when you've finished writing your novel? If the answer to those questions is no-one, then you could be in trouble.
We all need help when writing, or doing anything for that matter. The help could be picking out spelling mistakes that both you and the spell-checker have missed, or suggestions for phrasing. Sometimes it's a general critique of a chapter, a story or a novel, or just someone to run an idea past. Whoever we are, we all need people we can trust to give an honest opinion on our work.
The most obvious answer is a writer's group. I'm lucky in that I have a local group that I can attend each week where we critique each other's work as well as practise our writing through exercises. There is a lot of support and we also email each other when we want something specific.
If you aren't lucky enough to live near a local group, then why not set up a yahoo or a facebook group and share that way?
Another way to meet fellow writers is to join a creative writing class and continue to meet after the course has ended, or see if any other writers are local enough to meet up once a month.
However you do it, you will need people no matter how famous you become. Stephen King has a group of several people he can pass a finished novel round and won't do anything else on it until he has received their feedback.
If you haven't got any help at the moment, see what groups are available or start your own.