Is the time before conception important? i lived healthy but had some panick attacks a few weeks before ovulation, and therefore used benzodiazepines for 3 days. does this have any impact on the egg that's been released?

Not specifically. You are born with all the eggs you will ever release & there are exposures through your life that have some impact. By the time you release mid adulthood the information contained in these eggs is set. Whether or not a "good one" is released reflects that lifetime of exposures of which the weeks before are less reflective of your emotional state than your nutrition.