Car chugging at 75 mph

Hello, stop "worrying about a fuel pump". Have fuel pressure checked -- it's likely just fine. If you're "not super mechanically inclined" - there's not much to offer suggestions to you as far as what you can do without taking it to a professional. Testing on what is going on must be performed using diagnostic tools which cost thousands of dollars and are a large investment for technicians or repair shops in general, which is one of the reasons there is a cost to performing diagnostic testing. It's essential and available and helpful, and will give you some direction on what to do going forward. Sounds like your vehicle has been great for you -- perhaps you can get many more miles out of it! Good luck.