estradiol after miscarriage to bring on period?

Hi, I found out 9/2/10 that my baby had stopped growing at 8 wks and there was no heartbeat at my 12 wk ob visit. I had a d&e on 9/3. At my two week follow up everything was fine: no abnormal pathology from the miscarriage, bleeding had stopped, pregnancy test was negative. I was given the go ahead to ttc again. I've been checking my bbt's faithfully and haven't ovulated that I know of.
It's been a little over 6 wks and I haven't started a period so I talked to my dr. and he gave me Rx for Estradiol (estrogen) to take for 21 days.
Everything I've seen online talks about taking progesterone after the estrogen for this. The dr. said I probably have low estrogen levels...is that why I only have one medication to take? He did also offer a month of b/c but as ridiculous as it may sound...I just didn't want to be on b/c when we are wanting so badly to get pregnant.
Just fyi, I'm 37, have a healthy 10 yr old son, and was told the miscarriage was due to chromasomal reasons.
I got pregnant after only one month off of b/c when my new husband and I decided to ttc.
Can I get my period back, and ovulate just from taking a course of estrogen? Could I ovulate while taking it?
Any advice is much appreciated. Thank you!