Hi, Me Any My Girlfriend Had Unprotected Sex After 19days

Hi, me any my girlfriend had unprotected sex after 19days of her period, then next day around 23hrs later she had OPTION 72- 1.5mg (dr.morepen) contraceptive pill. It's 10 days now and she didn't have had period yet. By 6-7 of every month she bleeds but this time she is not bleeding, but last night she said that there are 2-3drops of very dark blood (blackish) coming out of vagina. We don't understand what to do now? Is everything normal? Should we wait for her period or check ourselves with pregnancy test kit.?? Please help doctor she is in panic.