The first time I had contrast, they didn't actually plan on doing it. The tech came in and said, "They saw something during the scan and want to enhance it with contrast." Of course I started shaking like a leaf on the table. Turns out it was nothing more than that, just an area that was harder to see. All was good. So, now I'm getting contrast AND I'm freaking out, recipe for disaster, right? Wrong. It was totally fine.
Also, I had a reaction to the iodine contrast for a CT, so you'd think I am predisposed to react to contrast. Nope. MRI contrast just like saline, nothing to it. (They treated the iodine contrast with prednisone and I was fine in about 15 minutes.)
You'll be fine as well.