could I be pregnant?

So I got my period may 21-26 had unprotected sex June 2 and took the morning after pill that same day. Six days later I started light bleeding/spotting and it lasted for 6 days so I wasn't sure it was my period or just a side affect of the pill. My expected period is on the 18 and I started a slight brownish spotting on the 19 so is this period or was the first one my period.? Could I be pregnant?