Baby measurements off

So I went to the doctor on 05/03 because I have having some bleeding. The doctor couldn’t really tell me why I was bleeding but the baby was fine. I got to see/hear the heart beat on this day baby was measuring 7w2d (I should have been around 7w5d not much of a difference) I keep on bleeding on Sunday so I went to the er they let me see baby and they told me it was measuring 7w3d with a heat beat of 152 and the let me know why I was bleeding. So on 05/09 I got to my first official OB appointment and they did a vaginal ultrasound and the baby measured 7w3d the same that it did on Sunday. The doctor wasn’t concerned because the baby had a strong heart beat of 160. Has this ever happened to anyone and everything turned out to be fine?