Yesterday was Day 4 of NaNoWriMo and I have so far kept to my goal of 2000 words a day (with an exception for the day before Thanksgiving and the day of Thanksgiving since I will probably be working crazy-long hours those days).
It can be hard to keep moving forward. Sometimes I have to go back to remember what I've done (for example, what I named a place), and it's hard to resist the temptation to start changing things. But I must resist!
Another difficulty: getting stuck. I have a very loose outline of what I want to do, but by nature I tend to write by the seat of my pants. That's fine when I can sit around and play with things endlessly, but when I'm in a time crunch I've learned the best way to get unstuck is just to change the scene.
Seriously. Just end the scene, however you can, and get to the next one.
Usually I can come to some sort of decent conclusion to a scene, but not always. Sometimes I can seamlessly transition to the next, sometimes I have to just put a hard chapter break.
And sometimes - only very rarely - I just leave myself a note to finish the scene later and move on.
That's allowed. The goal is 50,000 words of a novel. They don't have to be contiguous and the novel doesn't have to be coherent.
I feel fine about bailing out of scenes when I have to. I'm on track to finish and I'm going to keep at it.