I been spotting brown for a couple of days now what is the problem?

Pregnant?: If you're sexually active, you'll have to rule out pregnancy. Purchase and perform a home pregnancy test. They turn positive at about the time you're one week late.

Spotting: There are many causes of spotting, and most causes aren't serious at your age. Spotting can be from ovulation, can occur a few days before & after your period, from intercourse. Having polyps or fibroids can also cause spotting. Serious causes can be cervical infection, cancer of the cervix or uterus. See your doctor if it continues. Regular gyn visits is best to prevent major problems like cancer.