I felt pretty good at 4.5 weeks too. 6 weeks the extreme nausea kicked in and by 7 weeks I was throwing up at least once a day. I hope the feeling good stays around for you! I'm finally starting to feel a little better.
BFP 7/25/09, M/C 8/21/09;
BFP #2 10/13/09, Derek Joseph born 06/30/10;
BFP #3 7/21/12, Andrew Chase born 12/27/10 at 26 weeks 4 days
Hope it stays that way for you! It has for me... I haven't had any m/s at all. I've gone through periods of EXTREME fatigue, but that's been the worst of it.
Re: I feel rediculously good!
No offense, but I barf in your general direction. Quite literally.
Enjoy it...and hope it lasts.