Period or Pregnancy ANSWER PLEASE?

My lmp was 4/25/11. I was due this past Monday on 5/23/2011. My fiance' and I are trying to conceive and we bd's on 5/6-5/10 and 05/14, 5/15, & 18. I had creamy white discharge with a hint of pink on Sunday May 22(this has never happened to me before). Then Monday 5/23 (af day) there was no period, discharge or cramping. At around 1am on Tues 5/24 I felt my cycle coming. I wiped and there was blood. I put in a tampon and took a hot bath to ease the cramps. Woke up at 6:30am and the tampon was no where near full. Put another one in, took it out at 4:30pm and it too was not full. It's like I am bleeding off and on (with cramps off and on) but not heavy. My normal cycle is always on time (every 29 days) and lasts 4 days with the first two days extremely heavy (2-3 full tampons). I took a preg test today and it came back negative. What is going on. Should I test again in a couple days? What could be going on??