Glad you came here to vent!
Don't feel bad - I'm sure that no lasting harm as been done.
As for easy answers to parenting teens - none LOL! My kids don't have ADHD so I can't speak directly to that but, I do work full-time+ and always have my kids with me.
It can be challenging!!!! I know!
In order to get work done I've always addressed - first - how to handle the kids. We have to expect them to have bad days and unexpected issues. I've always found it easier for me to work around their schedule and needs (as much as possible) than the other way around.
If you have flexibility in your office set up - separating your work area from the rest of the house would be wonderful. Kids are noisy and there is no way around that - at least that I've found so far. If you don't have that ability maybe you could at least move the computer so that he isn't in the background on Skype calls. Then bargain with him if he is quiet/tv muted while you're on phone calls. If he does that then he ...?? - figure out what motivates him to behave and have it agreed upon ahead of time.
The other thing that saves us is routine. I don't know if you have the ability to have a set a routine but, it certainly helps us! Once the kids know what the schedule is (and that it is consistent), their expectations will adjust. It will take a while but it is worth it.
I also try to 'reward' them as they adjust to changes - doesn't have to be a thing - could just be an activity, time etc... but it does work to reinforce. I found that works better than taking things away (esp. things that I really rely on to help to occupy them in times of crisis or important phone calls).
Perhaps you can send a letter/email to your contact explaining that you had an unavoidable family situation and suggest a follow up meeting time. I bet they understand - we all have family issues
That is a universal fact I think.
Hang in there and find a way to treat yourself tonight - a movie/tv show, a yummy desert and a good cup of coffee always works for me!!
p.s. best 'punishment' I've found so far is having kids write sentences - positive sentences that reinforce the good behavior you're looking for.
i.e. I always obey my mom, especially when she is on an important telephone call. Sounds kinda corny but it does work! Kids do not like to write over and over.