1998 Chevy Cavalier Pink Liquid Pouring Out

1998 Chevy Cavalier 4 cyl Automatic 105700 miles

I just bought the car and went for an oil change. I ended up getting a transmission flush and a valve cover gasket replaced at 5pm. I drove the car again for maybe 5 mins to another place then 5 home with no problem. After 11pm, I drove for about 10 minutes and then I could smell something. Light smoke was coming out from the hood. When I finally opened the hood I didn't see anything unusual but I thought maybe something was overheating so I opened the engine cooltant. My uncle put some in there the day before, but I wasn't sure which brand/type, I'm hoping he put the right stuff. So at like 3am, I went home and heard a loud thuding noise like I ran over a dead animal or something was hitting something under the hood. Puddles of I think pink coolant was all over the parking lot. The coolant seemed to be coming from the right front area, i'm guessing the engine coolant area/tank cuz it was wet. How could this happen? Did my uncle put the wrong type? I thought maybe I did't put the cap on tightly but there was way too much all over the ground to be coming frm the cap. Thinking why was it smoking in the first place! I can't believe after just having that stuff done, this problem appears.