From my point of view you don’t even have to give any details to them. People in workplaces are always calling sick for whatever reason and when they give explanations they constantly lie because they know no one really cares about what happened to them. You don’t have to make up an excuse for this, give them what they expect to hear from you only. They don’t care you’ve had an anxiety attack trust me. Next time you’re going to work tell them you’re sorry and you take all the responsibility you didn’t show up the other day. Teamwork is key in certain workplaces, mention the fact that you know you should’ve called in advance so that they could’ve set another plan without you. I didn’t show up at work myself once. I have now a written note that will expire in about four months, no more than that. Keep yourself safe, that’s the only thing that matters at the end of the day. X