You asked about brief psychotic disorder. Here are links to 2 articles, from PsychCentral's archives, on the subject:

https://psychcentral.com/disorders/b...rder-symptoms/

https://psychcentral.com/blog/kony-2...otic-disorder/

You can also search the internet for additional information. It appears there may be quite a bit of it out there.

You mentioned, initially, you were kicked off the volleyball team. But then you said you just dropped out with nobody knowing why. So I wasn't exactly sure what happened there. As far as what to tell them, should you ever see them again, you really don't owe anyone any more of an explanation than you care to give. You could just say you were ill or just say you had some things going on elsewhere that consumed all of your time & energy. So you just had to drop out for a while... something like that. But there again, you don't owe anyone an explanation.

You mentioned being concerned about the possibility of your symptoms coming back. It's important, I believe, not to become overly worried about this... not to dwell on it. Just keep up with your medications. Hopefully you're also seeing a counselor or therapist. (If you're not please do so if you can.) And, beyond that, get on with your day-to-day life to the greatest extent possible... (including volleyball?) I'm so glad you're doing well now. My best wishes to you...