Overheating all of a sudden but runs fine?

I was driving down the highway doing about 65 and noticed temperature gauge starting to rise, that was early this morning. So, I pulled over to let the truck cool down added fluid and went on my way. It's has been 3 or 4 times now overhearing the truck seems to run fine but here the past couple days when I start truck it's shudders a little then shuts off. I have to do this like 3 times before the truck stays running and runs fine. Any ideas would be greatly appreciated, thank you.