losing oil pressure

I have a 96 Dodge ram pickup. With 128K miles

Today on the way to work, i noticed my oil
pressure guage all over the place.
Staying at 40 for a few minutes, then dropping down
for just a few seconds. Then back up to 40.

I recently did an oil change, but dont see how i could have caused
this problem in doing so.

Any suggestions on what it may be?

Thanks for any help, Brad

oil level low?
Maybe you knocked the pressure sensor while changing

Oil level is fine, no lost oil.

im guessing the sending unit is bad

i called my dad and he said the same thing,
hopefully this is it.

i appreciate the help!!!!
have a good weekend