Yes, you're out of luck if you didn't buy. My guess is another fare sale will come along in middle to late September, for travel up to mid-December or so. But that's just a guess. There could be another one this week, or none for the rest of the year. But since loads drop off in the later months of the year, I think we can expect one by the end of September.
Until then, check on
www.bestfares.com on the News Desk for "Snooze You Lose" fares. While Best Fares doesn't do as good of a job as it used to, you still can find good info there. Also, use the Fare Watcher feature at
www.travelocity.com, and you also can get good info at
www.air-fare.com. Just check frequently, maybe daily, in case there's a temporary drop in price.