No period

Amber
My periods were always regular I had my daughter in June 2012 and got the Maraina (merana?...mer-an-ah) right after...in July 2014 I got it removed and me and my SO have been trying since I got my period in August...2 weeks after I had some spotting (pink at first but turned kinda brown) and I was expecting my period in September (this month) on the 8th and it still hasn't came. I've taken 3 pregnancy tests all purely negative (no faint lines). What would cause this? Should I go see my doctor?