dark brown spotting with odor

in need of advice...

my husband and i have been trying to get pregnant for two years...we are in the process of starting infertility consultations...i'm on no meds...and am a pretty healthy 25 year old...i have never been pregnant and my periods are never normal. february of this year i had two cysts removed from both ovaries... fun stuff...from february to july of this year i hardly got my period and never at the same time month to month. july i got my period and was so excited because it happened on its own that month! great! it was normal and about 7 days long! then august hits and september too and i'm having the same thing happen that you are...dark brown discharge that is pretty light as far as amount goes... and it comes and goes throughout the two months...so far i have kept record from august to today october 17th it has occured 8 times...and when it goes away for a couple days..my husband and i will do the deed and then it comes back again...what the heck? i have an appointment next month with my gyn and had an ultrasound about 3 weeks ago and it came back normal. my last pregnancy test i took was more than 4 months ago...but when you keep seeing negative results you really dont rush to the store to buy them anymore...i should own ept or first response by now! i have seen some posts from women saying they had the same thing and that they were some weeks pregnant ...i'm not sure what to believe anymore...infection or pregnant? i have no other symptoms...no cramps...some headaches and tiredness but i attribute that to work.

advice anyone?

thanks,

jkom