What Does Bleeding After Bowel Movement Indicate?

The past two days I've been noticing blood on the tissue after I go to the toilet. I'm unsure where the blood is coming from, but it is consistently there after using the toilet.
I'm a healthy young woman on birth control - my period is not due for another two weeks. I'm in a relationship and was last sexually active a week ago. I've never had a UTI before, so wouldn't be able to recognise if this was one.
I have no other painful complaints, no discharge, itchiness or rash. I am unable to attend my practice for the next fortnight, but some reassurance and an idea what could be causing this would be very helpful!
Thank you.