I've had to change one of my site's home page to HTTPS from HTTP. I had plenty of links coming into the HTTP page and was performing well in Google against many of my targeted search phrases.

I did a 301 redirect from the HTTP page to transfer the link juice to the HTTPS page (and to prevent duplicate content issues) but my search rankings have tanked which indicates no link juice has been transferred. My PageRank has vanished - which I'd expect - but I'm really surprised that the SERP rankings fell off the face of the earth. Anyone have any ideas how I can recover from this? I've waited a couple of months since the changes took effect just in case Google was taking time to check it out.