My LMP Count Says I Am 6 Weeks And 4

My LMP count says I am 6 weeks and 4 days pregnant, but my trans v ultrasound says its 4w1d and no cardiac movement, I believe that a fetus only develops heartbeat from 5wks onwardsso I did not panicked, am I correct? I was also given progesterone suppository for 1 week, but from yesterday i noticed a thin threadlike blood discharge from me but not continueus? Is it normal?