The general rule of thumb for accutane is a milligram per kilogram.
This works out to about a milligram for every two pounds.
In general, they put you on a half dose your first month to minimize the side effects, I don't know how much you weigh, but it sounds like a reasonable dose. If you continue having the side effects, stop taking it and talk to your doctor (either your dermatologist or the other doctor of your choice).
Hope it works out for you!