That makes sense; you should note that those are "automated" test responses that are designed to check for "server-wide" issues without human intervention, and should not be considered as being DreamHost responses or replies. If they had found a "server-wide" issue that impacted many users, that test would have triggered an alarm with the staff.
Yes, unfortunately that is exactly the position you are in if you completed the ticket generation process. You ticket will have gone into the queue and will be dealt with as soon as possible.
That's a reasonable assumption at some level, but that is precisely what those first-stage automated tests are designed to detect. The fact that they did not identify a server-wide outage, if that is to be trusted, indicates the problem is localized in such a fashion that it may well be just you.
Hang in there! I hope they can get your site's fixed in short order.