Hey Emmy. I bet the tulips are beautiful and changed the day for you. Enjoy them!
I have locked my 2 year old in the car also. I would bet half the parents out there have locked a small child in a car. You did exactly the right thing.
In order for me to feel safer about not locking them in again, I bought a magnetic key holder for my car. It holds an extra key and I keep it stuck to the car frame right behind my front license plate. It is hidden from the outside. It has been stuck there for a year, and I have had to use it once or twice. It was pretty inexpensive, and it seems like I got it at Target. That way, I don't have to call anyone, or dig up an extra key from home.