Is Susten 200 Mg Is Safe While Having A Delay In Periods And Negative Pregnancy Tests?

hi..... my doctor suggested clome from3-7 days n duphaston from 20-27 days ,,,,,,,,,,,,,, i used those medicines for 4 months ........ i stopped last month . my last month period was 11-2-2014 i didnt get period till now.......... i had done 3 pregnancy tests all r negative........ but now my doctor suggested me to take susten 200mg for 5days........... is it safe............?