My partner and I have been trying for almost 3 years to have a baby but nothing

So my partner and I have been trying for almost 3 years to have a baby but nothing.. we have had times where we thought I was pregnant but wasn't.... I suffer from ovarian cysts regularly so that is usually the cause of missed periods but this time I feel different I'm 4 days late i feel sick in the stomach.most of the day , slight head ache sometimes, lower back ache, abdominal cramps like period pain and slight cloudy discharge ......could I really be pregnant