Yes Lani, Weekly testing fom now. So that's great!

Thats a good idea to push it back to 8 weeks. I had dating scans with both my boys, both just days away from the 8 week mark, and there was no missing the heartbeat, so 8 weeks will be perfect. You know, I had the brown spotting too, but did with DS1, which was fine, so I was not concerned at all. But that's great you've had none. I read that you can be really sick the the molar, I was not sick at all, not even a day. But I obviously had the enlarged uterus because I was huge, and was just putting it down to baby #3.
Hang in there, the 8 week mark will be here soon. Are you having you scan done at an obstetric ultrasound centre? If it was a molar (which it's not) I am sure any sonographer would pick it up anyway, if that's what they are looking for in particular.