Continual Spotting

I was just wondering if anyone has had any of the symptoms I am currently having. My period is really irregular and my fiance and I have been trying to get pregnant for 1.5 years now with a lot of heartbreak each time I miss a period and end up not pregnant. The one thing that is always constant about my periods is that they are really heavy. In december I thought my period was starting because I had some bleeding but then it only lasted for a couple of days and was very light. Since then I have had a small amount of brown spotting and a couple of days with some bleeding after sex. Does this sound like pregnant spotting or just a screwed up period? I know I should see the doctor, but after so many disappointments I kinda wondered if any pregnant person had these symptoms.

Thanks!