I would recommend if you DO go to a car wash is to use rinse only. But take in mind guys this is "Recycled" water from their system on-going due to the requirements/regulations they need to meet.

Ensure you let it run for a good 30s or so+ to allow only water to come and only use the rinse! Best to go late at night to do your two bucket wash and use your own product as you will have a cleaner car, keep it protected and not damage your wax/synthetic wax!

But if your paint faded so quickly, its probably needing a good machine polish and a decent sealant/wax to protect the paint!