Hi Rach, The only reason your dates would be wrong would be if you had an extended period of time on the injections to help stimulate your eggs before pick up. That is the problem i had. Because i was given extra injections (13 in total and then trigger inj) it put out the dates from my LMP date. So therefor i had to work out dates going off my egg pick up, and count egg pick up as day 14 and work back in order to come up with a "new " first day of LMP.

Eg- LMP commenced 21 may - sat
Inj from - 26 may - thurs
trigger inj - 7 june - tues
egg pick up - 9 june - thurs
Transfer - 14 june - tues
1st b/t - 23 june - thurs
2nd b/t - 25 june - sat
3rd b/t - 28 june - tues
4th b/t - 1 july - fri

So all up if you count my first LMP start date i would have been a week ahead due to extra inj. I was told that you should always go 14 days prior to pick up to give you an accurate date.

Good luck for your u/s, i am sure everything will be fine. Asd for the cramping i had a bit as well and it went after a week or so. Hope this helps was not too confussing.
Kas