I am a 28 year old female. I always had  regular menstrual cycle of 28 days in length. Since the last 4 cycles, my periods have been constantly irregular. At first they came in 31 days, then in 20 days, then in 26 days and this time around it's already been 30 days and my spotting, which usually starts 5-6 daya prior to my periods, started yesterday. But still there is no sign of it. I am unmarried and a sexually active female. I Have safe sex once or twice a month with my partner. Would be obliged if you can provide me some guidance regarding this health issue.