When my ford 150 xlt 2003 truck is running it gave off a fishy smell why?

What is your question?

There's a fishy smell in the trunk when I drive it. Before fluids were running out underneath not sure where it was coming from. I took it for a oil change and noticed leakages after and I took it back and he topped it off again with fluids. sometimes it shuts off when driving but I think because the cable to the battery needs replacing. I also noticed a recent leak from the I believe from the muffler, a small hole spitting out fluid.

What makes this problem better or worse?

When driving

How long has your 2003 Ford E-150 had this problem?

A few months