I Am A Frazzled Mom

Ok, first of all I have been trying to figure out a way to approach this subject but I think I just need help. That is what it comes down to.
I have a wonderful son that I love so very much. He is the sunlight in my life. I have always called him my "sunshine". He is now 10 and it is getting very hard. He has ADHD and I just don't know what to do anymore. He is on medication, and it works most of the time but his mood swings are terrible. It is to the point I just don't even know him very well anymore. I am losing who I am too. A couple of years ago he started having seizures too that have affected his behavior. He has been seizure free for two years though so we think we may be out of those woods.
I just need advice and I think I am at a point where I consider all of you my friends. I know that ADHD is very common and sometimes over diagnosed but without a doubt he has it. There are some other traits that go along with ADHD that are very frustrating. I just don't know where the line between -Oh that is just his "condition" and You know better than that- is. Impulsive behavior is something I just don't understand. Some of the things he does I just stand there and think "What have I raised? I have totally failed as a mother". Tears are always there, I just can't hold them back anymore. I love him so much and want him to know that but it is SOOO hard to reach out to someone that is so mean and nasty to me.
I got a phone call from his teacher about a month ago and it keeps running through my mind "Mrs. Dover, do you allow him to treat you with disrespect at home?". What kind of question is that???? What kind of mother LOOKS for disrespect? Maybe it IS my fault and I DO mess up.....
Sorry to be mopie, that is not who I am, I just hope someone out there that comes to our blog will be able to help me better understand.For an "disorder" that is so common, I feel so very alone and confused. It has been a very hard road and he isn't even a teenager!!!!!!!
Thank you so much. We love all of you and have such a fun time with this blog.