all I can say for sure is any time you hesitate or choose not to do it, it validates your anxiety and makes it even harder. The solution is to, well, not do that. And it may take a while.
I wish there was an easier way, believe me.
I wish anxiety disorders were easy to fix, but they are going to be an uphill battle. No magic pill or technique will cure it instantly. I am on the mend personally but find I still have good days and bad days. It takes conscious willpower and a conscious effort to change the way your brain operates. With that said you are best to, as cliche as this sounds "face your fears". Think of it this way: If you don't take the course what are the consequences as opposed to if you do?
If you don't take it, you will face a decreased chance of landing a job, you will not have that opportunity, and you would have psyched yourself totally out and reinforced the power the anxiety disorder has over you. Let me tell you, it doesn't have power over you - you, me, and everyone on this site create mental distortions that make us feel powerless when in reality we are not ever powerless. It's always a conscious choice to let your day be defined by your goals and aspirations, or to let your day be defined by what you fear.
If you DO take this course, however, you will gain important knowledge, you can start reversing your mentality by going through with it even if it scares you, you can get a job helping people in that way, and you also state to yourself that your anxiety does not govern your day or your future. We all live on this planet, face the same hostilities and risks, and all have the possibility of illness or dying early - but you don't have to let that dictate your future.
Anxiety cannot hurt you. Has it killed you in the past? Since you're writing this topic, I can say it didn't. There is nothing to fear in anxiety - it's a natural human instinct. Everyone has it and if we didn't have it, we wouldn't have evolved as successfully as we did. Heck, we might have gone extinct.
Anxiety disorders are basically that primal instinct being applied to situations unnecessarily - it is all perception, how you view it. Perception is not reality and I think it's difficult but not impossible to overcome this skewed way of thinking with time and a conscious effort to just get on with your life.