Yes, you can go to your office. But do not make any contact with the person who has been sick. Also, make sure your workplace is clean and hygienic. Wash your hands regularly with soap or use a sanitizer that has 60-70% of alcohol content. Ensure that face masks and paper tissues are available in your office for those who have a runny nose or any other symptom, along with closed bins for hygienically disposing of them. Sanitise people working around you to stay at home even if they have minor symptoms.