It's understandable that you would be concerned about this, but I read your post as you still having 5-7 opportunities to interview. There are clearly statistics showing the average number of rankings submitted by those who do and do not match, but in practice there are also site-specific variables like fit, how sites rank you, and how many positions they have to offer. At the end of the day, people with 10 interviews can go to Phase 2 and individuals with one interview can match in Phase 1. Going into the process with more interviews is safer in general, particularly in the context of specialty tracks with few available positions, but don't count yourself out yet. If you receive any interviews, go into them with your best foot forward and only concern yourself with Phase 2 if that time comes. Other than practicing interviewing skills, there's not much preparation one can do anyway, as we cannot predict which sites will go into Phase 2. Hang in there!