I have been taking 300mg of generic wellbutrin XL for about 2 ye...

I have been taking 300mg of generic wellbutrin XL for about 2 years. I recently started doing some research on side effects because I always feel dazed and out of it. It never feel like I am awake—it’s like I am in a constant fog. I consistently feel groggy, can never think of the correct words to say and have trouble concentrating on even mindless tasks. I spoke to my doctor and he said that I can go off of it; that sometimes antidepressants can have these types of effects on a person. How long will it take for the brain fog to go away? I really hope that these are symptoms from the medication and not something else because I don’t want to live like this anymore. I’ve began to taper down—I’m supposed to take 150 mg for a week and then go off of it. I'm so sick of being dazed and confused!!