Seemed like there was smoke coming off the engine again

I picked up my car (2004 Dodge Neon) today from the repair shop. It had the radiator replaced; the mechanic told me it had transmission fluid in it and he had to replace it. It was overheating and the transmission light had come on when I took it in.I picked it up, drove it home (about 25 miles) and no problems but when I got out of the car I thought I smelled something a little funny, like something burning maybe. I took the car back out for a mayb 5 mile trip and when I pulled in the drive it seemed like there was smoke coming off the engine again and I smelled the smell again. The gage didn't show the car overheating but it may have been just slightly over where it usually is.
I'm freaking out after such a major repair that there may be something wrong again. Is this normal? What should I do? The shop I took it to is closed tomorrow and I am supposed to use the car for a short (45 miles, maybe?) Trip Sunday. It is very cold here, about 28 degrees. I don't know if that would make the smoke seem more apparent or not.
Thanks!