Very confused about period & spotting!?

No I don't have an STD..I recently had a pap like a couple months ago. But anyway my fiance and I have been tryin to conceive for a while now & haven't ad any luck...well last month my period was 5 days late and unusually light & short...usually I have a heavy flow and it lasts about 6 days...well this one was light and 2.5 days...I took a pregnancy test the day before this period started and it was negative...well 17 days after the first day of my last period I started spottin a brownish LIGHT period that only last 2 days and now it went away...I took an ovulation test right before this spotting started since we are tryin to conceive and it had one dark and one light line...I took a pregnancy test today and it was negative...I called the nurse & she said it sounds like I'm pregnant & to make an appointment if I have a negative hpt...which I did & made the appt today...just wondering if anyone has experiences this before and what happened? My appt aint till the 28th and I'm a little impatient =/