An hCG level of 77 can be considered low, especially if your period is already 10 days late. However, it's important to remember that hCG levels can vary greatly between individuals and pregnancies. It's best to consult with your healthcare provider for a more accurate assessment. They may recommend additional tests or monitoring to determine the health of your pregnancy. Try not to panic as stress can also impact hormone levels. Stay positive and seek professional guidance for a clearer understanding of your situation.