Your HCG levels for 19 days post transfer (~5 weeks gestational age of fetus) are well within the norm for a singleton pregnancy in which HCG levels typically range from ~800-20,000.
Congratulations and good luck with your pregnancy.
Just to add to Peekawhos answer:
if your body doesnt expel the fetus naturally within a certain period of time (im not sure what that time is) then medical intervention may be required. In some cases, serious complications can result (infection, calcification of tissue) if the tissue is not passed.