Your priority right now is to go to all of these interviews, as that is the most important thing.
However, as others have alluded to, it was not appropriate for you to schedule your sub-I during interview season and miss so many days. Sub-I's should be scheduled to be done by September (or latest October), so that applicants have time in November, December, or January for time off or lighter rotations then to accommodate all of their interviews. The whole point of a sub-I is to increase your chances of matching into that particular program that you are presenting rotating on. Going to 1 interview during that time is a bit of a risk (though most decent programs would understand) -- however doing 8 interviews during your sub-I month is crazy-talk (as that is like missing 1/3 or more of the rotation, especially if you add in time for travel and pre-interview dinners), and no wonder the department head is not pleased with you.
With all your time gone from the rotation (and the department head unhappy with you), I'd presume you have nearly killed your chances of getting into that particular program, and you might have had a better chance matching into that program without even rotating there at all. So there was no point to a sub-I, if you'd have to take so many days off. However, it's best to still go to all of your other interviews, so you don't miss out at the chance of matching to those places. Just try your best to make-up the days on weekends if you can. If not, the department head will continue to be angry, but there isn't really much you can do about it other than try to make up the time as best you can.
Sorry if I seem hard on you, OP - it's just that this situation could have been entirely avoided with a bit of planning, and reading these forums about 6 months ago when everyone was asking about how to schedule their audition rotations. You are not being reprimanded for having too many interviews as your title suggests, but rather for your improper scheduling of a sub-I in the midst of interview season when you needed this month off for interviews instead. (For future applicants, please take a lesson from this and schedule your sub-Is from July to September, so that you don't have this issue of being forced to schedule multiple interviews during your audition rotations.)