Suggest Remedy For Irregularity In Periods

lets start with my last few period dates. July 12 2010, i skipped august, september 4, and october 22 all of 2010...I have always had about a 30-32 day cycle, but within the past few months it has been very strange. this last period was extremely heavy and about 2 days after it stopped i noticed like a brownish pinkish tint when i wiped. then every so often a small blood circle would drop down. What do you think this can be? Do you think I can be pregnant because me and my boyfriend have been sexually active.