Im fatgue, achy and haven't had my cycle fo 4 months. what's my malfunction? and no i'm not pregnant.

Anovulation: Unless you are on a form of birth control known to knock periods off such as depoprovera, you are probably dealing with anovulation (absence of ovulation). This is by far the most common cause of absent periods after pregnancy. In this particular case, you want to see you doc, who will help you "jump start" your periods by giving you medication.

Anovulation: If you are normally regular and then stop having periods for 4 cycles, that warrants a medical eval.