I'm sexually active with my fianc & have been spotting brown & pink for 3 weeks. only noticeable sometimes when i wipe (no need for a pad). periods 1?

Need to examine: It is not feasible to provide a meaningful opinion without examining you, however, at a minimum you should do a pregnancy test. If you miss your period by 4-5 days, do a home pregnancy test. If the result is negative repeat the test 4-5 days later unless you get a period by then. Use first morning urine and follow the instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex if you have sex. Get HPV vaccine

Spotting: Irregular bleeding is one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. Infections ; hormonal changes can cause spotting. If there is a concern for pregnancy then do a home pregnancy test . There are many options available to help regulate the menstrual cycle. Schedule a visit.