Late Period, light brown discharge, Negative test?

Hi, so i have never done this before so here goes.

Well I have been usng the pull out method with my partner ( I know its not 100%) for almost a year now. 

Last month my period was 9 days late but when I got the spotting and the full on period came like a few hours later.

So this month; I am now 7 days late and I had a wee bit of spotting last night and then nothing this morning which is really odd for me.

I took a pregnancy test 2 days ago( 5 days late) and it said negative..

Also, about 2 weeks ago I had the sorest nipples ever you couldnt even touch them it was just to painful

 I have had endo in the past and Ive had the opperations to remove it

Ohh I came off the pill in may and it is now september here is a wee list of me recent periods-

23rd May ( last period on pill)

23rd June (fully off)

1st August (9 days late period)

Before I went on the pill they were like clock work, i have all of them written down, yes I am OCD but yeah

Has anyone had this before?

THANKS :)