Is it possible that my period is missing/late because of a ruptured cyst and STD or is it a chance that I might be pregnant nov 8 - the first day of the worst period I ever had. Extreme cramping and vomited for the first time due to period. Nov 11- ruptu

With . With a negative pregnancy test you have identified two possibilities: the ruptured cyst and the chlamydia. Another strong possibility is that you are not ovulating or that the previous cyst has prevented you from ovulating. This may be a one-time issue but cysts can occasionally recur. I usually offer oral contraceptives to women who have had "the worst period" ever and those having unprotected intercourse to offer protection against an unwanted pregnancy.