Water – Strange water pressure

First, the square footage of the house doesn't mean a thing in this case. The important factors are water pressure and supply line size and the height of the fixtures above the pressure tank and the pressure tank size. The well pump fills the tank, then the air bladder applies pressure to the water in the tank. a check valve stops water from going back towards the well. When you call for water, the internal tank pressure pushes it through the pipes.

A few different problems may exist here that would cause your problem.

The tank pressure membrane may be waterlogged. It will still show static pressure, but drops to a very low PSI when a faucet is turned on. Often, you will hear the pump cycle more that usual in this situation or you may see the water pulsate instead of a steady flow. What is your static vs open line pressure?

Another common problem is the backflow check valve is leaking. This causes water to be pushed back towards the well. the tank pressure will slowly decrease between pump runs.

If this problem has been long standing, then the pipe size going to the second level may be too small. Second floor fixtures or ones a longer distance away should be fed with at least 3/4 inch line, not 1/2 inch line.

The last factor may be that the well is not delivering enough gallons per minute. If the pump has to run for excessive time to fill the pressure tank, this could be the problem.

I'm sure there may be a few other items to check, but these are the most common problems.

I was able to fix the low water pressure issue by slightly opening the valve stops.

I was able to fix the vibration issue by finding a procedure online to empty my water lines.