Fatefully
I posted this a few days ago and perhaps you might have missed it.
Week 1 is actually the start of your LMP. The reason for this is under normal circumstances, it is extremely hard to pinpoint the exact moment when the sperm meets the egg. With IVF, it is calculated the same way. Therefore, when you get a BFP at the end of your 2ww, you are already considered 4+- weeks pregnant.
There is also a slight difference in calculating your EDD depending on your IVF protocol. Below was taken from
http://www.ivf-infertility.com/calc_preg.php
1. If you conceived naturally and you usually have regular menstrual cycles, use the first date of your last menstrual period (LMP).
2. If you conceived following insemination, IVF or after replacing frozen embryos in natural cycles, use either your LMP or the date of ovulation.
3. If you conceived following IVF or ICSI in a stimulated cycle, use the date of egg collection.
4. If you conceived following intrauterine insemination in a stimulated cycle use the date of insemination.
5. If you conceived after replacing frozen cleaved embryos whether in a HRT cycle or stimulated cycle, use the date of replacing cleaved embryos.
6. If you conceived after replacing frozen blastocysts, use the date of replacing blastocysts.
7. If you conceived after replacing fresh blastocysts, use the date of ovulation.
I believe you did FET and had your ET was on the 3/11. Since you are now pregnant, you were actually 2 (gestational) weeks pregnant during your ET (3/11). Wow! Amazing isn't it? I know this sounds strange and is very confusing. Look on the bright side, we actually gain 2 whole weeks. So base on the calculation and from the wesite posted by
Ron as of today you should be 4w 5d.
To answer your question about seeing anything during your scan this Friday (5w 1d), there is a 50% chance you might detect a heartbeat which generally takes place 6 ½ -7 weeks. So please don't worry if you only see a sac.