Period twice in november by december week late/short/diff. end january, no period positive preg trest. confused about conception and double period?

Pregnancy: lease consult your GYN for further evaluation of your cycle, blood pregnancy testing, hormone levels and thyroid function studies.

Sometimes it makes: little sense, but an alteration in your normal pattern should alert you to the possibility of pregnancy, which you wisely did and voila. You should confirm the test with a healthcare provider before you take the next action, whether that be to keep the baby or not keep. As for conception, it likely occurred before or right after your short December period.