Just got home from work and my mum said that she saw Yoshi walking on the bottom of the cage for a few seconds..... she seems perfectly okay. Maybe she was just looking for food?
I wouldn't worrie to much about that, I see my females on the bottom of the tank every now an then, it's when males are on the floor it's time to worrie
Then she's probably just exploring. She might always check the bottom of the cage. I had one who did it several times a day. Neither of the two I have now has ever been on the bottom of their cages...it's a personal choice your chameleon will make.