There is no direct contraindication between Wellbutrin and diazepam, but there are some important considerations:
If you were only given one dose (or a short-term prescription):
Taking your regular Wellbutrin dose is generally safe.
Avoid alcohol or other sedatives until the Valium fully clears (Valium’s half-life is ~48 hours, but the effects taper sooner).
Monitor for excessive sedation or confusion.

If you were prescribed diazepam for ongoing use, speak with your psychiatrist or primary care doctor ASAP. They can:
Assess risk/benefit of ongoing co-use.
Adjust doses or recommend an alternative short-acting benzodiazepine, if needed. Consider psychotherapy or SSRI/SNRI augmentation for panic attacks, which are safer long-term.

No interaction among those medication are present and it should be safe, however, you need to be careful if you are a smoker, then dose needs to be adjusted or smoking cessation is recommended.