Sorry to hear about your "odor" problem. Maybe there is a local public fountain you can take a dip into!!!
However, the problems you describe are fairly common, but may be tricky to isolate. Let's try some basics:
Relieve the pressure from the bladder completely. Let the well pump fill the tank completely and bleed any air from the system using the faucets with the pump running. Again, with the tank full of water, close all outlets and charge up the bladder to about 60PSI. Most systems work fine between 45 to 65 PSI. Anything over 70 is pushing it. The tank needs to be charged when full, not empty.
Monitor the pressure as you draw water. Does the pump kick on constantly when the pressure reaches the low limit, and off at the high limit? This will help tell if the regulator is working properly.
Is there any pulsating water pressure at the faucets?
When you are sure you have a full tank, no air in the system, is your second floor water flow ample when the tank is reading 60psi?
There are a few "if's" here. Depending on how the pump behaves and the pressure responds, you have to determine if the problem is with the pump and volume of water being delivered to the tank, or if the pressure regulator is properly operating.
If you are still seeing any pulsating water pressure at the taps, then the bladder is water logged again. If the bladder pressure drops too quickly, then most likely the volume of water from the pump is low. The pressure should remain fairly constant at the tank if all the functions of the pump and regulator are working properly. Good Luck
I do not have a well, and not a water expert, but I have a recurring water leak problem and thought I'd share my experience in case it helps. I recently experienced a problem similar to what you described - water kept running but nothing I could touch was leaking. I could hear water running (high pitch sound), but could not locate the leak. I finally checked under my house, in a crawl space, and it was very wet. It turned out that the leak was underground in a rusty old galvanized pipe. I am still cursing that P.O.S. and the fact that any fool ever used galvanized rust prone metal.
One other way I've been able to detect water leaks is by using a cheap stethoscope. I once had a very expensive plumber come out with an electronic stethoscope attached to a read-out, but since then have been able to narrow in on leaks in walls by using the stethoscope (and saving myself about $1000 / event).
Best Answer
It is highly possible to run a well down in level to the point where it is effectively dry. Water is not an endless resource.
As you pump water out of the well casing the level in the casing drops. Depending on the depth of your well, the height of the water table, and the capacity of your well you can pump the casing dry.
Then, water refills the well casing over time and now you have water again. If you are in an area that has experienced low rainfall, overpumping from agriculture or other issues your water level couldn't be extremely low already.
Another issue could be a clogged screen on your pump. Only a well service could help you with this.
Try moderating your water usage and see if that helps.
Good luck!