I Had My Last Periods On 26th May At Night.

I had my last periods on 26th may at night. Had unprotected sex on 31st may and took an I pill within 8 hours. On 6th June I bleed nd I'm still bleeding for the third day from then. It is less heavy than my normal periods but it is continuous and associated with a bit cramps and pain in leg(like I usually have in my normal periods). I've a 30 days cycle. What is actually happening with me? Should I go through a pregnancy test?