What Causes Delayed Period And Negative HPT After Using Clindamycin And Clotrimazole Vaginally?

Hello Dr. I took clindamycin and clotrimazole vaginal capsule at 20 Feb . and my normal MC period is 8 march still I haven t get in period and pregnancy test which I have done It shows negative result. Can u tell me what is reason for it? Its side effect of this drug which I have use in vaginal???