When Should Duphaston Be Taken?

hello, my doctor prescribe me with duphaston for 7 days. i started taking it yesterday at 9.20 am and 9.20pm. however, today i forgot to take it because im stuck with my jobs. As a result i take it at11.20am. I have been informed that must be taken on time. What should i do? what time should i take duphaston tonight. please help me doctor..im afraid there will be side effects on that. tq