I also had a poor run of Gem Pulls I did 3x 50 gem pulls and had only received some 4*, I don't remember the exact number now but think I worked out I was just under average based on %. My most recent pull got me a 5* not one I had been chasing (a character quest one) but at least it was one.

I'm now thinking I'll be saving my gems for the future... power creep should see better girls appearing further down the line.