Sudden Abnormality in my periods

It is not uncommon for a woman's cycle to go through many changes throughout her lifetime, even after being very regular for an extended time. It is more common in the "peri-menopausal" years, usually beginning around age 35, but there are many things that can cause a disruption in your cycle, endometriosis, for one, but also other reasons that are just "normal" fluctuations. I wouldn't worry, but I would make an appointment to see an OBGYN if you can, especially if you are trying to conceive.