Two things I can think of, based on my short dalliance with Concerta so far and some research I've done on how others dealt with the side effects I experienced at first:

1. Maybe your tolerance for methylphenidate went down during the time you weren't taking it, and you need time to get used to this dose

2. Make sure you're eating and drinking enough all day, as not doing so can definitely trigger headaches for a lot of people (which might be worsened by noises)

With luck, someone with more experience or expertise should also hopefully be able to supply some further suggestions for you when they see this.