Did anybody have different measurements with baby? Like growing too fast at the beginning? let me…

Did anybody have different measurements with baby? Like growing too fast at the beginning? let me explain on Tuesday July, 21. Baby measured a week behind (5 wks and 2 days) I was supposed to be 6 wks and 2 days. Later, a week after on July, 28 it measured (7 wks and 4 days) I'm supposed to measure 8 wks and 2 days. Then, I went to get checked yesterday July, 31. Because I was spotting it measured (8 wks and 5 days) is this normal?