Your presenting symptom is post coital bleeding after period over.
If its just the day after your period, and you are able to time exactly when you finish because usually there is no set time to suddenly just stop.
You are able to tell by your own vaginal fluids if there are any traces of blood it.One day after you think you have finished period and then making love. Its probably the action of intercourse its just sort of clearing the rest of that away.It would naturally come down a number of hours later.
So dnt worry about it .
**One really important thing : Are your PAP tests up to date ?
Keep haviing regular checks, if you are worried and you arer continuing to have bleeding after intercourse
, not just the day after your period.Then you would arrage for a gynaecologist to look at this.
Any unusual bleeding after sex (not day after period) should always be investigated.
If you get abnormal cells on PAP TEST,then go for COLPOSCOPY
to detect underling pathology.