Dark brown blood can occur during the first few weeks of your pregnancy. Bright red blood should be your main concern as that suggests active bleeding. The cramping may be caused by your growing uterus. It's important that you bring this up with your doctor as soon as possible so that if it is a serious problem they can help you ,and your baby.
I wish you the best of luck, and remember to contact your doctor as soon as possible.
brown bloods old blood and can be normal in pregnancy as well as cramping. if your worried give your doctor a call.