Thanks for the query.
Irregularity in menstrual cycles can occur due to many causes.
So just by symptoms we cannot come to one conclusion.
You once consult gynecologist, get examined and go for blood test
Which can give more accurate results compared with urine test.
If the possibility of pregnancy is ruled out by these, you can take tablets for withdrawal bleeding and then for regularization of the cycles with your doctor's advice.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429