Miscarriage

I say this with so much sadness but so much peace. I am in the middle of miscarrying right now and it's much tougher than expected.  
I am wondering how soon after a miscarriage can you try again? 
My doctor says not until my hcg levels are at 50 or lower, but mine were pretty high and she said it could take up to 6 weeks for that. 
I feel so many people have gotten pregnant after a miscarriage so much quicker than that. 
Advise?