I just cant get a hold on these nerves.

Im currently around 7 weeks pregnant with my rainbow baby. I have had a few ultrasounds already to make sure baby is in the right place etc. I had one last week showing a really nice strong heart beat. But... for the past 2 weeks ive been spotting and its doing my head in. Its only brown and only when i wipe. But its so scary. It stops and starts ill have a few days with nothing then it starts again. I just cant help but feel that this is going to end badly. I lost my second pregnancy at 15weeks. This is currently my third. I have one healthy 17 month old son.