When talking about your job as an activity during your day, you should use the term "work" - not "my job", "my work", "my office", or any other variation.

I had an interesting coversation at work today.

You can use the phases "before work" and "after work" to talk about things that happen in the morning before someone goes to work or in the evening after they leave.

She goes running in the morning before work every day.

What are you doing after work?