please help

so I had unprotected sex a month ago and my period was supposed to come today. well two days ago on Wednesday I had some spotting so I was sure it was my period . Thursday I also had some spotting until the middle of the day. now there is absolutely nothing going on. does this mean I could be pregnant or what's going on? I've never had this happen with my periods before and I just took a test and it's a BFN. 

Vote below to see results!