Awww honey its horrible that waiting - I do know...

Okay is it possible you ovulated later than you think you did? The level of 202 for 4 weeks is good... Sometimes early u/s can be iffy. It is very possible & probable that there is not a detectable heartbeat that early. Many obs won't u/s until 7weeks for that reason.

I would suggest a couple of things...
Firstly a reapeat hcg today if you can get in...
Reapeat it in 48 hours - if that level is doubling that's a really positive sign.
If it were me - if the blood work is looking good I would have a repeat u/s on Friday this week. By This Friday you should see a nicely beating heart and of course a fetal pole...

Sending you a big cuddle my love..