Hi,
You should consult your physician and get herself clinically examined and relevant investigations needs to be done to find out the cause of pain and blood in stool.
Basic tests like USG abdomen,
complete blood count, pt inr and urine routine microscopy may be done. There may also be need to do a colonoscopy and upper GI endoscopy.
Take plenty of oral fluids and healthy balance diet.
It's always advisable to have protected intercourse. Ipill has also got some indications. Consult a gynaecologist too.