My LMP does not match with the pregnant week after ultrasound scan. Shd be wk 7 but its wk5. Only has gestational sac.

Of course. Based on LMP may not be accurate as your ovulation may be late. Note : not everyone knows when their ovulation is. That's why an ultrasound is needed to determine how far along u are. Even I have a period tracker which can track my ovulation day too, my pregnancy was still early than I thought I was. So yup perfectly normal! Too early to see your fetus so come back again for another scan. By 8 weeks all is clear, the heartbeat and your fetus. That's why it's always recommended to do a scan at that week.