Knee pain and period

Aly
I've been having some serious pain in my left knee, like I usually do during my periods, but right now my knee pain is getting uncomfortable to the point I don't want to put any weight on it. 
What can I do to reduce the pain? I've taken a hot shower and I have a blanket under my knees with a heating pad. I don't take anything for the pain, I like to try something that will help naturally. 
Anyone else experience this?