M.J.
If you're not happy with the side effects, there's no point in continuing. There are so many other medications out there for ADHD; don't put up with unacceptable side effects. We made the mistake of sticking it out with Adderall and Vyvanse (had to call 911 on this one, he was smashing holes in his wall and threatening to jump out his window) and those two were total nightmares for our son. A lot of the time, side effects don't improve over time (although things like appetite usually do).
Definitely talk to the doctor again and ask to try something else. if Metadate works well otherwise, there are a number of other medications in the same family, including Concerta and Focalin. Another one in the same family may prove to be a better match.