I am going to say:

• In spite of all my efforts, I couldn't pass the final exam and I have to attend all these sessions from the beginning again and start everything from the outset! The same old story!

But I was wondering which one of these two options can be indicative of what I said above?

a. Now, I have to be back to square one
b. Now, I have to go back to drawing board

As you can see within the dictionary definitions:

"To be back to square one" means:

If you are back to square one, you have to start dealing with something from the beginning again because the way you were dealing with it has failed.

Also,

"To go back to the drawing board" means:

If you say that you will have to go back to the drawing board, you mean that something which you have done has not been successful and that you will have to start again or try another idea.

To me, they both seem to be the same and I cannot fond any distinction between these two idioms. I was wondering if you could help me with it.

I am going to say:

• In spite of all my efforts, I couldn't pass the final exam and I have to attend all these sessions from the beginning again and start everything from the outset! The same old story!

But I was wondering which one of these two options can be indicative of what I said above?

a. Now, I have to be back to square one
b. Now, I have to go back to drawing board

As you can see within the dictionary definitions:

"To be back to square one" means:

If you are back to square one, you have to start dealing with something from the beginning again because the way you were dealing with it has failed.

Also,

"To go back to the drawing board" means:

If you say that you will have to go back to the drawing board, you mean that something which you have done has not been successful and that you will have to start again or try another idea.

To me, they both seem to be the same and I cannot fond any distinction between these two idioms. I was wondering if you could help me with it.