Hi, White Fox.  I take Wellbutrin, too, and I know that usually, doctors like you to increase the dosage slowly, although it may be that 150 mg. could do the trick for you.  The maximum a person can take is 450 mg.  Do you not trust your doctor, and is he/she a psychiatrist?  If you're not seeing a psychiatrist, you might want to consider one because they specialize in medication management and have a lot more knowledge about the different antidepressants.  Nine days is not a long time to be on it and expect a big difference; for some people, it can be 6 - 8 weeks before the full effect is seen.  If you take too much, there is a risk of seizures but I don't know how big a risk it is, especially if you've never had that problem before.

Hope that helps, but do keep in touch with your doctor.