Wrong Gestation Age, Is it possible?

LMP ko was Dec 10 lalabas na 11-12 weeks ang baby. Nagpatransvaginal ako 2 days ago and sabi 14 weeks na daw. If 14 weeks nagkaperiod pa ako ng dec 10 moderate to heavy bleeding pa nga with no pain and anything because its period so di ako naalarm. How can it be possible that im 14 weeks already if nagkaron pa ako ng december 10? Nagspotting ng dec 30? Possible ba magkamali ang transV? Help me po mga moms thankyou!