You may be pregnant. was your last period the normal length? was it shorter and lighter than normal? If so it's very common to experience light blood flow, and/or spotting when the fertilized eggs implants into the uterus. Take a pregnancy test girl! Buy a few.. if you think you could only be a few weeks pregnant use the first urine of the morning when the HCG hormone is at it's highest.. If you get a negative, test again in a few days, and in a week. Follow up with your GYN. They can order a simple blood test *which yields results in an hour or less* that will confirm the hormones being present. Your doc will prob order another in a few days following the first test to check the increase in the hormones. Best of luck to you and I hope that Ive helped! Take care!
The menstrual cycle is not perfect. You can be a few days early or a few days later than the previous month. Don't forget, many months are long, so the actual date is often 5 weeks not 4 on the calendar.
Even the idea of wanting to be pregnant can delay the hormones!
Good luck.