IllToxic: I cannot give you medical advice (for that you need to see a doctor)... But I can speak from the standpoint of an ADHD'er who has about 15 years experience with stimulant medications...
It sounds to me that you are being dosed too high... The symptoms you are describing seem to fall in line with what I personally experienced when my doctors had me taking too large of dosages...
It has been documented that there exists a small percentage of ADHD'ers that are hyper-sensitive to the stimulants, and therefore a relatively small dosage (say, 5mg of Ritalin, or 5mg of Adderall 3x daily) will work wonders for these patients...
When I was first diagnosed at 19, I was prescribed these large adult dosages of Dexedrine, Ritalin, etc... and it took a couple of years to "dial-in" my dosing... and strangely enough, I, as a 6'5" big male found the greatest relief of symptoms by taking a 3rd-grader's dosage... but it has worked wonders...
I wish I could speak to the efficacy of cannabis treatment for ADD/ADHD, but I am only now gearing up to move to Colorado for treatment for my MCTD... If the cannabis aids my ADHD (as it is purported to do), well... that will just be an added bonus...