Endometriosis can only be diagnosed surgically. However, everyone experiences the sympotms differently. Some people have them all the time/daily, others have them more at different times in their cycle, and for others it feels more sporadic/random. So, what you describe may very well be how some women experience endo. Personally, I experience fatigue almost daily, but certain symptoms are more limited to my period. As far as pain levels, those vary for me based on a variety of factors (stress, activity level, diet, etc.). I hope that makes sense.