Do ultrasounds date 2 weeks ahead too or is that just going by lmp?

It depends.: Pregnancy calculations and "Menstrual Math" as a friend of mine calls it, can be confusing. Universally, dating a pregnancy hinges off the LMP or an early ultrasound and uses 40 weeks as the total length of pregnancy. Counting from the first day of your LMP, this calculation includes 2 weeks where you actually weren't pregnant.

Pregnancy: Ultrasound measures precisely the size of the fetus or embryo therefore giving very close number for your gestational dates,\.