Why has my period come a week early and is brown a clump?

Many possibilities: If this repeats itself you may want to go and get examined, but menstrual irregularities are very common and have multiple underlying factors, most of which will clear up without problems.

Irregular periods : 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.