where did my follicles go?

I am on my second round of clomid (50mg).  The first round I ovulated fine, but did not conceive.  I was referred to RE and they just put me on it again day 3-7.  I took it, went for a follicle scan and they just saw 30+ follicles all under 10.  I was told to wait a few days and come back the second scan showed 1 follicle at 13, and 3 follicles at 11.  So I went again 3 days later and all that was there was 1 follicle at 13.  Where did the others go?  I was hoping to go back and have at least one be over 18.  I'm not sure what to think.  Where did my eggs go?  The nurse said that there wasn't any free fluid to suggest that I ovulated already, but that my lining had thickened.  What does it mean?  Any help?