It is hard to say exactly what may be going on. It is possible your period was causing the bleeding, but if not, here are some other things it may be!
Sometimes when bleeding during vaginal intercourse happens this can be due to a lack of lubrication. The body self lubricates naturally but sometimes extra lubrication is needed. When someone is using lubrication with a condom they should use water based lubrication. Oil based lubrication ( like lotion for example) can actually weaken the materials of the condom.
If someone is having vaginal sex for the first time, there can sometimes be blood present due to the hymen. The hymen is a thin membrane that partially blocks the opening of the vaginal entrance.Hymens can be stretched or torn during the first experience of sexual penetration, or with tampon use or other non-sexual activity. It can also be stretched with fingers. Some people are born without a hymen. It is important to know that while some people may experience blood due to the hymen stretching, many people may not experience it at all!
Sometimes bleeding after intercourse can be a sign of an infection. Some sexually transmitted infections (STIs) and infections that are not STIs like yeast or bacterial vaginosis can cause irregular bleeding.
If the bleeding continues it would be a good idea to see a medical provider. They can determine what may be going on. If you want to make an appointment at Teen Clinic you can give us a call at 303-442-5160