I appreciate your query.
I pill does interfere slightly with the menstrual cycle, but it is not responsible for permanent alteration in the pattern of your menstrual bleeding.
There has to be definitely some reason for your delayed cycles, if earlier you were having normal 28 - 30 day cycles
One reason could be polycystic ovarian disease
, for which you need to get your FSH, LH, DHEA, S. free testosterone
, SHBG, Fasting serum insulin
, OGTT etc, as well as a pelvic ultrasound
Another reason could be derangement of thyroid hormones or adrenal hormones.
Also, stress, sudden weight loss
or weight gain, anaemia, unaccustomed strenuous exercise, might cause altered menstrual pattern.
You might have some other pelvic pathology for which you need to consult your gynecologist at the earliest for detailed evaluation.
Sometimes, there is a condition in which there is premature ovarian failure
, where delayed periods occur much earlier than the expected age.
All the best.