Try not to be perfect!
Yes, you read that right, try not to be perfect!
As a medical professional, you are taught not to make mistakes. But, the thing about learning a new language is that you must make mistakes. Lots of mistakes! That's just part of the process. Fear of making mistakes is the first obstacle that you must overcome. And, you must overcome it quickly!
You simply cannot afford to be paralyzed (or partially paralyzed) by the fear of making mistakes! To learn to speak Spanish, you must practice SPEAKING! And, if you are worried about making mistakes, you're going to be doing a lot less speaking.
And so, it is very important that you recognize at the very outset that perfection, if you ever reach it, is something that is way, way down the road. In the meantime, feel free to make lots and lots of mistakes!
Making mistakes means that you are trying, and you know what? That's all it really takes to learn another language. All you have to do is to keep trying—make enough mistakes—and eventually you'll be speaking Spanish conversationally!