I had my period last nov. 10-15 and then i had some sort of light period on dec. 1-4 and then again on dec. 10 till now i am having brown spots?

Multifactorial: Your abnormal bleeding patterns may be the result of many factors. Depending on your age, any hormonal medications (birth control) you may be on or even something organic like a polyp or fibroid in the uterus, this may be readily explainable. In order to understand what is happening here, I think you may need to see your OB/GYN and have a discussion about your bleeding patterns and an ultrasound.