notnsane Check the imagepoint in the particle you created, that also indicates where the particle will be directing itself. Check also for gravity, that could be affecting your particle and that is why it goes in a different direction.
You can also use PIN behavior to attach the particle to the Plane.
Without an example, screenshot or capx, it is kind of difficult to guide you, so it could be easier to determine the issue.
Also give it a look to the forum, there are a couple of articles/questions about particles, but I do not recall them right now.