I haven't had sex but i missed my period last month. (feburary) & right now i'm having brown discharge. what's happening?

Brown = old blood: Irregular periods are 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.

Wait and see: This might be the start of your period, but a lot of different things can disrupt your cycle. Also, when you are younger your cycles tend to be less regular and predictable. If you have no period for more than 3 months it would be wise to get checked.