Hi. This happened to me for the last two months for the first times in my entire life. I too am very regular ever since my first period. But two months ago about four days before AF actually arrived, I spotted. I thought maybe I was pregnant and did waste the money on a test. Of course BFN. Then last month, it happened again. Not sure where this is coming from all of the sudden. It seems as though just as I started TTC, everything went haywire!
I haven't worried too much about it though. I just had a pap three months ago which was normal, so I am guessing that this is just life. Things change all the time with our bodies. If you are really concerned, call your doctor though. They can probably give you a better explanation that I can.