LIGHT PERIOD! PLEASE HELP!

I started my period at 16th May and ended my period around 21 May.  

I had unprotected sex with my boyfriend at 1st June (after ovulation) . We did the withdrawal method (He didn't ejaculate in me. And I know precum can get you preggers). 

My period is due on 13th June and it came on 10th June. When I use a panty liner , it almost fills 3/4 of it. (sorry if too much info)  But when I use a pad , its only light.. The blood looks like my normal period (has clots in it though)  blood but it's just light. I have had light periods before but not that often. Now this light period completely stops and lasts for 4 days only.  

ALSO I TOOK A PREGNANCY TEST IN THE MORNING AND ITS NEGATIVE. I'm taking another pregnancy test (maybe 4 weeks later) to just make sure that i'm not pregnant.

I've been stressed and nervous thinking that I'm pregnant but is it possible that my brain is probably just trying to mess with me?

I HAVE NO SYMPTOMS TOO.  Please help me. :) And also do share if you have the same situation as me , I would like to hear your experience. Thanks for your patience reading my question.

xx