I've noticed red fluid on the ground. and now sometimes when im at a red light and then hit the pedal when it turns green. it starts slipping. I'f I add more fluid will it fix this or is my trans already screwed. btw, can i add fluid myself or do i need to take it to an indie shop because most places won't add fluid bc there is no fill tube under the hood.

 

easy on the pedal mate.

Indy shop.
Or crawl under and do it in a parking lot.
That is how I did it.

Ruined a shirt too.
Even if they changed the fluid, it may still slip.
Put in Lucas Transmission stop slip stuff.

 

No, it is most likely not ruined, but you need to quit driving it "TODAY" until you can have some one repair the leak and then change the fluid at the same time.
What year and how mant miles on the truck, do you have a check engine light on the dash?