Good luck, I just got prescribed the same med, I've been taking it for 5 days now. No effects so far but we shall see. I'm already taking fluoxetine and it helped a bit but I still have problems with motivation do that's why I got prescribed Welbutrin
My doctor said it might cause insomnia (didn't do that for me so far) and decrease apetite (it did, also I felt really nauseous and unable to eat for the first few days but I'm not sure if it was from meds or stress, I'm in a REALLY terrible life situation rn).
Overall I've read many good things about this med and it seems to be good for the type of depression I have (aka being very tired, no motivation,apathetic kind). If you have more anxious-restless kind it might not be that great.
I hope it will help you, good luck!
Also if you don't have any other meds, Welbutrin might not help with anxiety that much. It's sometimes combined with SSRIs which work on anxiety a bit more (for me prozac aka fluoxetine helped a lot with anxiety, and it's an SSRI)