is the bleeding i experienced after plan b my period?

I am 18 years old. My friends friend molested me and may have had semen on his hands when he touched me down there. I took plan B on Monday April 30, 36 hours after semen may have come in contact with my vaginal area.

I think I had my period. It started on Tuesday or Wednesday with light bleeding and then it went into heavy bleeding. It turned into light bleeding almost as if my period was over and then went back into a heavy flow. Thursday it was pretty light to non existent. Friday the bleeding was gone. So, it lasted about 3 days. Was this my period for the month? I know it's suppose to throw your cycle off. My last period was around April 13-ish. My period was due between the 10th and 15th. That is usually when my cycle happens. I experienced this bleeding around May 8th. Could that have been my period for the month?

Is there any possibility of pregnancy still?

I took a pregnancy test (first response) on Monday and it came out negative. I have another one, when would be a good time to take it for an accurate result?