I have kinda a weird situation, the doctors think i may have endometriosis so they put me on a pill I only get my period 3 times a year to reduce the pain and possibly stop/slow the growths. I have had extreme breast tenderness for the last 3 weeks to the point i cant sleep on my stomach. Also, last week i has such bad nausea i constantly felt like i was gonna puke, but now this week i am fine. I haven't gotten my period for 3 months now and have one more month until i am suppose to get it. My question is how do i know if i get pregnant if i don't get my monthly period. Do i have to buy a test every month? I am not exactly specific on the times i take my pill daily, normally within an hour time range though. Also, with my breast tenderness, everything I've looked up said it was due to hormonal changes, should i still be experiencing this if i don't get my monthly period?