I have a shower diverter that drips (increasing) when I take a shower. I'm afraid I might go through what a friend who lives in the same townhouses went through losing all pressure and water in the middle of taking a shower. She had the internal parts which came in a kit replaced. Outcome was a large water spot on the ceiling below.

This afternoon I noticed the toilet water was low which it was not when I left for work this morning. The water pressure is low throughout my townhouse with 3 levels but mostly in the Master Bathroom on the third level.

Any ideas ?

The drip and the low pressure are not related. Start with the drip, that valve can be reaired, replaced. Is it a shower/tub and where exactly is the diverter knob?