Did you drink enough water to push up your uterus?
Do you mean no gestational sac at all or no baby inside the sac? Either you are much less than 6 weeks, or the egg hasn't developed or the egg is somewhere else. If you start feeling any pain around that area you should contact your dr immediately as it could be ectopic.
My Dr didnt see anything until i was 9 weeks wait for acuple of weeks then reapet it again
Your probably to early to see anything
When I had my first appointment I was 6w 2d. My Dr said if I had come in an earlier we probably wouldn't have been able to see anything. So you are probably just to early, I wouldn't worry about it