It means your fetus was conceived about 8 weeks ago or so. All medical counting related to a pregnancy begins on the first day of bleeding when you had your last period before getting pregnant. This is usually a couple of weeks before you would ovulate, and therefore a couple of weeks before you conceived.
Hello,
Gestational age is the age of an embryo or fetus and is expressed in weeks. If the doctor said that the fetus was 10 weeks of age, then the gestational age of the fetus would have been 10 weeks.
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 and please do keep me posted on how you are doing.