35 year old female with late period

I am a thirty five year old mother of two. my period has always been on time and normal 28 day cycle.

I am not positive the exact day that my period was due but I know I have been with out one for about three months. I had a problem with pain pills, and got physically addicted to them after being subscribed them for lower back pain.

I am currently a methodone clinic patient and on a dose of 130 mg.
During this three month time period I also had an MRI on my lower back.

A week or so ago I bought two pregnancy tests from the dollar tree both came back negitive with out a doupt not even a slight line in pregnant spot. I do not think I am pregnant, but the posibility is there. I just dont feel pregnant. and took the two tests which were negitive. I took the test in the same two day period one during the day and one in the morning second pee.


My main question is are there medications like methodone or other drugs that would cause a missed period. I never have missed a period before and have had several drastic changes in body so it is hard for me to beleive that it is because of stress or health because I have had times in my life when I had a lot more stress and health problems and still had a period.

Also another article I saw about this on your site mentioned herbs that clean the liver helping with late periods, why is that?

Is there something about the liver needing to be cleaned, or in otherwords, having a strained liver and that causing a late or totally missed period?

And my final question is Could it be pre menopause?


Thank you for your time and responce,