You might want to make little joke of being over-dressed (the same would apply if the position was reversed and you were dressed much more casually than the other attendees). If you do, you need to be tactful about how you do this.
Alternatively, and assuming no-one else brings it up, you could ignore your faux pas, try to minimise your discomfort, and focus on the meeting - if you make a really positive contribution the others probably won't mind you being dressed differently.
If you are unfamiliar with the meeting attendees and/or don't know what the organisation culture is, it's best to check the dress code before attending a meeting.