I had really crazy anxiety the first couple days. Try to keep calm and remember that it's a physical process. Your body is feeling stress and anxiety, and your mind is searching for a reason. The reaction is totally out of proportion to the reality.
Try and separate from it, the way that you would from a friend who's hysterical and drunk. I'm sure you've been there, right? "Sweetie, I hear you, but let's talk about this when you're sober." Try to say the same thing to yourself. I kind of mentally divide myself into Rational Me and Anxious Me. "I know you think this is important, and maybe it is, but we're going to address it when we're not going through withdrawal."
And then, instead of focusing on the reasons, focus on the physical sensations that you're feeling rather than the mental activity. For me anxiety always registers as a tightening of the sternum. So rather than focus on the mental justifications, I focus on that tight feeling and try to breathe into it and relax it.
If you're like me, Anxious You will feel like you MUST think about all of those things you're worried about, the things you did that embarrassed you. You don't! Anxious You thinks those things are a tiger in the room and you need a plan. But it's not prehistoric times anymore, and you are not currently in a condition to be planning even for minor tigers.
Thinking about that stuff right now will do nothing except torture you. Once you're calm, you can think about them and decide if you need to do anything, like apologize or win back someone's respect. But right now, just don't get yourself into that spiral. Get a book, turn on the TV, and give yourself a pass to turn your brain off.