Noise when 2002 Jetta accelerates

I have a 2002 VW Jetta 1.8 Turbo

Recently, I was driving on the highway and it felt like the transmission was slipping a bit then the Anti Slip warning light went on and the car would not accelerate and would clunk when going from a low gear to a high gear. I pulled over, turned the car off and then back on hoping something was wrong with the Anti Slip feature (I might not be calling it the right name). Anyway, after that the car shifted just right. But as I accelerated on the highway or hit the gas suddenly, it made a low rumbling noise and did not have power it usually does. I tried two things. Both at a light and when moving at a slow speed, I put the car in neutral and revved the engine but the engine sounded fine. Only when the car is in gear to I hear this sound when accelerating.

Full disclosure, just last week I had it in because the car overheated due to a water pump. It ran great for three days. I’m not saying they are related…that is all of you to tell me.

The noise sounds like it might be a hole in the exhaust or something but from the compartment. By why all of a sudden?

Help…we just had a baby and the water pump just went on the Jetta and my truck just has the AC compressor changed so money is not free flowing…ya know?