Fetal age due to LMP should be 7.2 but ultrasound after spotting showed the gestational age of 6.5 with flicker. Normal or can be some growth issue.?

Maybe? Most women unless they are extraordinarily regular are not good at identifying their LMP. Also, of all the tests in medicine, ultrasounds are the most operator-dependent. Have the most experienced person in your area perform the test and interpret for you. Best Wishes!