4 days in on 18mg!!!

i just started on 18mg of concerta a few days ago, i'm also on wellbutrin/buproprion, a non-stimulant anti-depressant. first day, i felt a little crazy, lots of intense dry mouth, hard time focusing my eyes fully, sleepy for the first hour after it kicked in, but nothing too insane. these past 3 days though, i've had little to no appetite (having only eaten 3 or 4 meals over 3 days), hard time sleeping, irritability, and CONSTANT dry mouth. obviously i'm so new to it all i'll need to give it longer to settle in, but i wanna know what is normal and what isn't as common. i've heard most people saying they get their dosage upped so it balances out more, but everyone has different experience.