Help!

I have had no problem with my shower for the past month I've lived here. This morning I got up to shower and the water comes out of the tub but when I turn the knob to switch over to the shower absolutely nothing comes out. I have had no problems with water pressure so I don't think it is an issue with buildup. I have a shower hose with a head attached to that.

I unscrewed the hose to see if water would come out of the wall or if the blockage was in the hose. When I turned on the water relatively high, some water trickled out with much less pressure.

I took the hose into my kitchen to see if it was clear and I could send water straight through it. So there is no block in the hose.

Any advice would be greatly appreciated!!

Thanks