I have a 1998 Monte Carlo with 129k. Automatic with 3.8L V6 Z34… Just put new brakes, struts and had transmission filter and fluid changed at 120k.
I noticed yesterday a grinding noise comming from what I though was the right front or rear tire. Thinking front. I removed both tires when i arrived home and don’t see anything out of the norm.(realize i’m mechanical enough to change brakes and fluids)
Today on my way to work, about 15 minutes(75mph) into my drive the ABS light came on. I did ignore it, figured I had brakes just not ABS. About 5 minutes later the BRAKE light came on 
I also noticed that the dash lights were not as bright. I figured I could make it to the next exit. Then I noticed the car’s tach was running high 3250-3500(usually 2500+/-) in OD. When I let off the gas the idle dropped to 1500. I accerated and the tach would jump up to 3500 and then I could feel the car trying to go. I shifted the car from OD to Drive. And noticed that the tach didn’t jump much. I limped home and parked the car in the garage. My question are
“What is the grinding noise?”
“Is my transmission done?”
“Do I have so many issue I should just take it to a mechanic?”
You are going to need to have a scanner or code reader put on it. Thats where I would start. It sounds like the transmission is going into limp mode. This would explain the increase in RPM’s. Also, as far as finding the grinding noise, you are just going to have to physically get in there and take a look around. Check with your local auto parts stores, most of them will scan your computer for free. Get it scanned and post back with all the codes they find.
transman
No battery light? I have seen ABS lights come on in conjunction with the battery light,you are observing dim dash lights.Give the battery cables a inspection,espically the postive terminal,Delco batterys of your cars vintage leak acid at the postive terminal,maybe you have had the battery replaced (likely) but possibly your postive cable has acid damage.Don’t know about noise (alternator bearing?).