Hi,
Welcome to the ehealthforum. I am glad to help you out.
Bleeding with cramps can be due to hormonal imbalance or corpus luteum defect (the corpus luteum secretes the hormones for sustaining pregnancy till 12 weeks after which placenta takes over). In corpus luteum defects, there is increased brownish spotting and if this is the cause then you may need progesterone supplements till 12 weeks of pregnancy.
The other reasons could be ectopic pregnancy and risk of miscarriage. Hence get it evaluated from a gynecologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations, and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.