I'm so sorry for your loss. After losing the triplets, I was able to take provera to get things moving along so that we could start TTC again just 7weeks after I delivered them at19w4d. I was like you in that I felt like it would help give me some hope again if we started trying again as soon as I could. My RE didn't monitor betas with that loss so I'm not sure how long HCG hung around for. With my 8w3d loss it took exactly one month for my betas to finally be negative.
Me: 27 DH: 29
My blog: http://ttcwithpcosrpl.blogspot.com
PCOS, adenomyosis, RPL, & IC
7/09-1/10: Multiple cycles of Clomid and Femara (O'd once)
2/21/10: femara, follistim & repronex... BFP after cycle cancelled for "no response"
6/18/10: femara, repronex, ovidrel
RPL testing: elevated anticardiolipin IgM
8/23/10: acupuncture, femara, repronex, ovidrel
1/7/11: Triplet angels 19w4d due to IC Cadyn
3/30/11: TTC again! Follistim 100iu BFN
4/26/11: Follistim & Ovidrel
#5 Shirodkar cerclage & 17p
Our miracle baby Mason arrived safely 2/22/12