What Causes Headaches And Mood Swings While On Bupropion?

After being on Citalopram for two years, my doctor switched me to Bupropion SR 150mg, twice a day. The first week or so, it was working great. However, now I'm noticing some side effects that aren't so great. I'm getting headaches and I get angry very quickly. I also have started having crying jags over stupid things. I will take one in the morning and then I will take another in the evening. I've noticed that the time in between taking the two pills is when the anger gets worse. I just took my second pill for the day and my mood seems more in check, but I have a headache now. I have been reading a lot online concerning the side effects. Many people said that dropping down to 150mg did the trick for them, or even switching to the XL version. However, I'm worried about the fits of rage. If I have to take the pill at night to make sure the rage doesn't happen, what do I do?