Car trouble blues

Oh my, what a day. I finally had a doctors appt for my thyroid. Had an ultra sound and blood work done a few weeks ago, and was going to get the results today. When I got in my car to drive to the appt, which is a ways away, my car started acting up. It wouldn't accelerate and the check engine light was on. I was lucky to get it up to 30mph. So I turned around and called a local garage and then took it over there to have it looked at. Had to call and cancel my dr. appt. Of course when I got back in my car it drove fine. At the garage he hooked it up to see what codes came up. It appears to be a faulty sensor that works with the transmission. Thank God it's not the transmission itself! He suggested I take it to a Hyudai dealership to have it repaired. I am taking it in the morning first thing. It looks to be about a $300-$400 dollar repair. I'm glad I've been working overtime and put some money aside, but it is SO despairing that I was finnally getting ahead and then something like this happens. Well, as I said, I guess I should be grateful that it's not the transmission. Now I have to reschedule my doctors appt. First I want to wait and see what's up with my car. Oh well, I am going to try and focus on the things that I should be thankful for. Hope your day was better than mine!