Could I be???

My husband and I have been trying to conceive for about four months now and each month that lovely reminder that I am not pregnant shows up, just like clock work on the 28th day. This month though, I have passed that day, which was on the 13th. I don't want to get too excited yet, since it has only be a few days but it is unusual. I have had little twingy pains once or twice, but no cramping. Light to mostly nonexistant spotting, no pink or red just a little brown. Was wonderig what other peoples experiences where, not sure if I want to take a test yet, what do others think?