Turned off water to replace toilet and turned on water, now there's low water pressure. Used to be 60, now down to 15 . I didn't mess with anything, I just switched on and off. Now back on, & yes its fully on. What's wrong?

Pump or city water?
Turned off water to replace toilet Where did you turn the water off at? Was it at the angle stop suppling the toilet? Back to you. Tom