E.A.
Not messing with unnatural drugs is a good idea!
Even if you do not have regular periods, you can use the Natural Family Planning method (NFP) as described in books from the Couple to Couple league ( http://www.ccli.org/ ).
Here is the search page to find a teaching couple near you: http://ccli.org/learn/tcsearch.php
NFP is a Symto-thermal method (NOT the calendar or Rhythm methods which don't work right) which uses your base body temp and other signs from your body to chart out your cycle. Women with irregular or regular cycles can use this method successfully to get pregnant or not. It is the most medically safe, and also 99% effective! My husband and I used this method to conceive two children when we wanted and will continue using it afterward as a contraceptive measure.
BTW, most doctors won't know about this method or have limited knowledge about it. Contact Couple to Couple League for the classes!
Good luck and God Bless!