Is there such a thing as "late implantation bleeding"?

Hey there just wondering im really confused and i need your ladies help.

I had my last period 07/01/2018 and then i ovulated on the 21st my bf and i had sex on the 20th. My next period was due on the 04/02/2018 and it didn't come but then yesterday 14/02/2018 i had light bleeding and it still here today 15/02/2018.

I took two HPT tests today both negative

Is this my period or could i be pregnant??

Any comments would be useful. My first day of last period was January 10th. February 21st I started heavy bleeding but ended completely after almost 2 days. When should I take a pregnancy test? Is it possible this was implantation bleeding? Mahalo in advance

Hi I had missed periods on, 7may and my home pregnancy test was positive 2times after missed periods but on 17 I m having light pinkish bleeding from night on the same day I was having dark bleeding and 3rd still have lightly bleeding on 3rd day with cramping and I also do ultra sound but there is nothing in ultrasound I'm confused tell me please what I do?