Finished an original story

I finally managed to finish an original story. If I could only write every day (or rather night) I’d feel a lot better. I only wish I’d get round to finishing my novel. Why is it so hard? I suppose I’m afraid I’ll ruin what I’ve already written. All I need is a sort of start. A couple of sentences to set the right mood. Usually I manage to think of something much sooner. I’m afraid that if I don’t get it finished soon, it will never happen. It’s just going to be pointless.