I have a well and my pump is fairly new, but last week I started losing water pressure when I had a few things running at the same time. It is good otherwise. What could be my problem?

Maybe not a problem at all with the pump but a capacity problem. A pump can only put so much water through and then the pressure will start dropping. For a test, shut everything down and then start one thing at a time. If the pump runs OK with 2 devices and not 3, there is your problem. I have a well and if the DW is on and I try to use a pressure washer, it cycles because of pressure drop. When the dishes are done, PW works great. This is fairly typical unless you have a deep well, a big pump and a large supply pipe. Do you have a whole house filter or water softener? They restrict capacity, particularly the filter if it becomes clogged.