Spotting but no period?

This is only my second cycle off the pill and trying to conceive, so I don't exactly know my natural cycle yet. I do know it's at least 30 days long though. My last actual period started April 17, 2014, I had EWCM on May 5, 2014, and on May 25, 2014 I started spotting. I assumed it would turn into a regular period, (mine are typically really heavy, last 6 days with bad cramps, and even when I was on the pill it would be pretty heavy) but it is now day 4 of light, pink spotting, not even enough to fill a tampon, and not one single cramp. So something is definitely different, but I took a pregnancy test when I woke up this morning and it came back negative. Has anyone else had an experience with something like this? I don't know if I should go to the doctor to get a blood test, or if I should wait longer and test at home again...