First thing, the delayed period is not a side effect of the pills. The only side effect related to it, is that after stopping pills, some women may not have a period. But this won't exceed 6 months, after it they will have normal period.
It seems that you have a problem that started early before the 4 years. A normal period should come on its own with no use of pills or parsley juice. Since you are not having a normal regular period, this may indicate that you are not ovulating and therefore cannot get pregnant.
Ok, i will get deeper so i want to ask you: Since puberty
, was your period regular before ?