Implantation or ovulation bleeding or something else?

A few days ago I wiped it was bright red, only bright red this once and the next time I used the bathroom it was very light brown

Anyways I had this extremely light brown bleeding for 1 1/2 days then it went to pink with some brown for another 1 1/2 days

This lasted close to 4 days

My period hasn’t started

I took a test it’s negative

I did have unprotected sex 13 days ago

My period was suppose to start tomorrow

I am 36 1/2 years old and healthy.