I'm paying 133% intrest on a payday instillation loan and cannot afford to pay this what can i do?

I have a high interest payday instillation loan that I am struggling to pay off. The loan was for $2,600 and I am paying $154.41 every two weeks. I will have to pay the interest off this instillation loan before any money goes towards paying down the initial $2,600 I took out. The interest is 133.871% and comes to $10,171.24 is there anything I can do and is this legal? I live in Ca and this payday instillation loan was taken out through Speedy Cash.