New bleeding with discharge during sex usually points to an infection or inflammation of the cervix or vagina, such as cervicitis. It can also come from a cervical ectropion or a minor friction injury, both common and not serious. An STI is possible too, so it's worth ruling out properly.
Next Steps
See a gynaecologist for a speculum exam and STI screening, which usually means vaginal or cervical swabs. A pap smear is worth doing too if you haven't had one recently. Avoid intercourse until you've been examined.
Health Tips
Get checked sooner if the bleeding becomes heavy or you develop fever or pelvic pain. Please consult a gynaecologist for the exam and test results.