<p>@Bumble: It’s actually pretty simple:</p>
<ol>
<li><p>Apologize, but skip the explanations. They will only view them as excuses. (Especially skip “explaining” that the vacation they took you on caused you to fall behind. They will view this as blaming them for your failure.)</p></li>
<li><p>Make up a list of every item that needs to be made up. This will mean going to each teacher and owning up to your problem and getting them to help you create your list.</p></li>
<li><p>Make up a realistic schedule of when you can get the items on the list done. For the next several weeks(?) you should schedule as much of your “free time” as possible for working on your list. No going out with your friends on Friday/Saturday nights etc.</p></li>
<li><p>Stick to the plan</p></li>
<li><p>Treat the whole episode as a life lesson.</p></li>
</ol>