Hey FlowerChild (I like that name a lot!)-- welcome!....well, from my experience, I would try to address it from 2 fronts (you've already got what sounds like a strong treatment support for him)--
first, what's the situation at the school? have they expelled him? does he already have an IEP (individualized Education Plan)...he must be in 5th (?) grade so if you aren't already in contact with the school, now's the time to start meeting with them-- I'd start with the teacher but in my situation, I went directly to the principal (they have the power)...he must be having behavioral issues at school and I found that engaging any and everyone who would meet with me was critical...they observe your son in situations that you never can and, if they're willing, they can give you written feedback to help you understand what's happening and when...that kind of feedback can go to the psychiatrist to show him/her what the patterns are...for example, one of his medications might clearly be 'wearing off' at a certain time and they can help you figure out if there's a pattern to it (I remember one time, we found that right around 2pm, one of my son's medications seemed to be wearing off so the psychiatrist increased the dosage which helped)...
second, the thing that I really believe helps-- it helped me because it showed me that I'M not the one that's crazy and imagining his behavior and it helped my son because it was details that helped the psychiatrist...keep a log...start a journal or notebook now, and write down your observations...what's he doing when, what does he say he feels like (if he's bipolar, like my son's diagnosis), he'll learn to be able to tell you how he's feeling and in therapy they can work with him to recognize his mood changes and learn coping skills for each type...my son is 19yo and I still go back and read some of my now many notebooks to remind myself that it wasn't me, he was really acting odd and I didn't understand why...the more you do that and reflect on events that happen, the more (I found) you'll be able to tease apart the issues and the ways that the medications are influencing his behaviors...and that helps the psychiatrist figure out the best mix for him..
you sound like you're pretty new to this experience (is that right?) and I'm sorry you're going through this...it is such a hard journey...there are some great books out there for parents in your situation...one of my favorites that I read when my son was about 10 is "The Ups and Downs of Raising a Bipolar Child"--- here's a link:
http://www.amazon.com/Ups-Downs-Rai...95771&sr=1-9&keywords=parents+of+bipolar+kids
in addition, do not hesitate to call either of your supports (the psychiatrist or therapist) when you have a day like today...don't feel guilty about calling them...that is their job, to help you through these situations and help your child...if they're not open to your contacting them when in a crisis, I would look for another provider...once when my son was in 4th grade, he took off and ran away and I called his therapist right away...that was the first time he had to be hospitalized because when the police found him, he wasn't willing to promise to stay home so we had him hospitalized to keep him safe...and his therapist was right there on the phone with me figuring it out because I was a complete mess at the time and she talked me through it...I don't think I could have had the strength to take him to the hospital if it hadn't of been for her helping me get through it...this is so hard...you've found a great forum of people who have been through it...there are others with kids yours age that can be even more help to you...I just answered quickly because it seemed like you needed to know someone was listening and here for you...take care of yourself and do all you can to be kind to you...