I just flushed my toilet and took a shower and when I adjusted my diverter shower handle to make both the shower head and hand held shower work at the same time I heard a "thunk" sound and all of a sudden water pressure is gone and it s now trickling... I guess flushing and adjusting the shower valve made water pressure to go low any triggered something in the valve, please help. I have a Moen am valve and a Moen diverter valve.

Your pressure is likely still fine but you have no volume. Have you closed the hand held knob yet and still have to water?