Brown discharge 19+5 week

Hi, On 17 weeks, i having bleeding went to A&E, they said both of us are fine. Just go back rest and monitor the bleeding. Few days later it stop and come back with spotting for a day. We call and asked them. They request us to go down to check. We went down to check, everything was fine. Last week, i having brown discharge abt 4 days till today. I am not sure is it because i am overwork/walk too much or other reason. Before the brown discharge, i went back to office. During midnite i have brown discharge till today. I am abit worry. I really have no idea what is going on. Previously, i have 1 miscarriage so i am abit paranoid. My husband ask me monitor as we have an apt this friday.