That is a great question, and one that is best able to be answered by your primary care doctor
or ob/gyn. In general, if you truly had your period it means that you are not likely to be pregnant, but on the other hand there are many caveats for why this is not always the case. There are several other causes for vaginal bleeding
and so it is important that you be evaluated by a medical care provider as some of these causes may be more serious and require varying treatments. One potential option is that you have incurred a miscarriage, as this can definitely present as vaginal bleeding. Another possibility is that you have cervical inflammation from a variety of sources, such as gonorrhea or chlamydia, and this can also lead to bleeding. There is also the chance that you experienced "implantation
bleeding" when the embryo implanted into your uterus and you are indeed pregnant. Again, it is very important that you make an appointment with your doctor to be tested for pregnancy. If you are trying to get pregnant it is very important that you take prenatal vitamins daily and lead a healthy lifestyle abstaining from nicotine and alcohol.