I had the same problem last year. I was nearly 3 months pregnant and all seemed to be going well. Around 12 weeks or so I started a very small amount of spotting. I wouldn't really even call it spotting, but because my first pregnancy was so high risk I called my ob/gyn right away. She told me I needed to go directly to the hospital for an ultra sound. I wasn't far enough along to do it on the belly so they ended up doing it vaginally. I didn't have good news. My doctor told me I was having a miscarriage and that the baby's heartbeat had stopped somewhere around 10 weeks along. It affected me terribly because my husband and I had been trying so long for our second child. We actuially knew the date of conception. I waited a few days and called my doctor back to schedule a d&c. I was told afterword that there was no rhyme or reason and no answers for why I miscarried. It was just my body's way of saying it wasn't a healthy pregnancy.
I have had friends who spotted throughout their pregnancy and had no complications when it came to a healthy child.
My advice to you is seek medical attention immediately. Make sure to see your ob/gyn as soon as possible. Look on the bright side... If nothing is found to be wrong, you just got to see your baby on screen a little more than usual. Best of luck to you.
Also, i'm currently pregnant and everything seems to be going well.....