[SuperStarAD]

Thanks for the suggestions! I realized that my problem was that most of my items didn't have a start date. Previously I used Appigo's ToDo, and it doesn't show start dates, so I've been setting the due date for the day I want to start. Nice that I won't have to develop bad habits like that with OmniFocus. :)
Now that I've entered start dates for every task that I can, and modified my Next Actions perspective accordingly, it works smoothly.