Well, if you want to think about people at your work in your sits, then it may be helpful to do a Compassion/Lovingkindness meditation. That way at least you can think of them in a useful way. Personally I find it very helpful to do the Compassion/Lovingkindness in the night-time sessions to help resolve the day in some way. On the other side, to help begin the day with some right view, I like to use other types of reflections in my morning sits. This helps to aid me through the day with people and situations I may meet.
If you have a strong attachment to your work, you can try, first of all, to do some walking meditation. Often people think the formal meditation is just sitting, and so they take this very, very busy mind into their sitting, but it can often help to do some walking first. I have found that becoming aware of the body, the feet, helps to calm the mind down before you sit. So if you tend to be very busy in your night-time sits, it may be very helpful to do a bit of walking before you sit down.
When you do sit, try to do the Compassion/Lovingkindness meditation and universalize these situations, so that we don't just focus on "my" work situation, "my" stuff. A lot of times we're just focusing on "my stuff", if we broaden our mind out a bit, take the situation and then universalize it, it may help to diffuse it. Learning how to take a situation and universalize it. This is very helpful, so that we're not just churning over our own situation, but broadening out to others in similar situations. This can help us to be less attached to whatever has happened during the day.
And if those don't help, it's also very helpful to strengthen your death reflection, because it may be your last opportunity to sit.