29 yrs old. no kids. no birth control for 5 yrs... 28-36 day cycle for the past 6 months. possibly infertile? what to do to find out?

Fertility: Having not prevented pregnancy and not conceiving in 5 years likely requires an evaluation. It is best to see you gynecologist or a fertility specialist who would do an evaluation to make sure that you ovulate, that your tubes are not blocked and that your partners sperm is normal. Treatment may or may not be necessary depending on findings. Good luck.