I Injured My Hamstring While Overworking At A Soccer Practice.

I injured my hamstring while overworking at a soccer practice. I injured it the week before. It has a red bruise on both of them but the left one is way worse. I don't know what to do and it feels really tender like it might pull. I can barely walk and it spread to my left calf. I don't know if I should ice it or heat it and I'm scared. Please reply as soon as possible