Hello ma'am and welcome.
This could very well be an early implantation
bleed but you must know that it will have to be confirmed with the help of a pregnancy
This will have to be done at least 2 weeks after your last sexual encounter or on or after the first day of a missed period.
Once pregnancy is confirmed you can confirm the implantation bleed as well, if pregnancy is ruled out then you might have to visit your doctor for a urine and vaginal examination.
Hope this helps.