There is no true diagnosis for perimenopause. Perimenopause usually starts in a woman's forties and may last for several years. If you go for a whole year without bleeding, then you can be sure you've reached menopause.
Many symptoms are the same as menopause. For more information about symptoms, go to:
http://www.redhotmamas.org/content/index.php?option=com_content&task=view&id=51&Itemid=136
Symptoms that differ from those of menopause include bleeding difficulties (i.e., heavy menses, prolonged menses, irregular menses- too close together or skipped periods, and intermenstrual spotting. So,your "unpredictable periods" may be a sign that you are in perimenopause. The discoloration is not a sign of perimenopause.