I am so sorry about your loss. My husband and I experienced a miscarriage last month. I was only 5 weeks along and my hcg levels dropped to zero rather quickly. I never got my period and we just learned we're pregnant again! Although we're super nervous, we are also very excited. So it can happen quickly! Best of luck!
I had a miscarriage in May, I was 8 weeks pregnant. We had been trying for nine months, the first time. I recently found out last week, that I am four weeks pregnant after trying only one cycle. So, my personally experience is it happened very quickly for me. I know what it is like when everyone else is having babies, even my husband's 15 year old niece is pregnant with no problems, which was extremely upsetting for me. I wish you the best of you luck.