Hi JoeBlogs,
I'm actually in a very similar situation as yourself. I'm currently a first-year graduate student in the direct PhD program for electrical engineering, but I realized that I don't want to do research work for the rest of my life.
This caused me a lot of mental conflict and agony for weeks, but now I feel I have reached a medium point. My advice is to continue to do what you need to do and think about what you really want to do. And the funny thing is, I found what I really wanted through a highly unexpected process so keep your mind open to ideas of HOW you will be able to find your true path.
Like you, I'm already behind in my courses and actually failing in one course. Yet, I feel as motivated as ever. I know what my future goal is now and all this studying and working is now just a means to that end. Also, I have the mentality that since I'm already pretty much in rock-bottom, I'm now gonna struggle to become one of the best EEs! It sounds crazy, but that new, seemingly impossible goal really motivates me.
Right now I'm redoing a test a got a 20/100 on LOL. But I ain't lettin' nothin' stop me. I don't care if it takes years to get to where I want. Like Brian Tracy said, "Never consider the possibility of failure." Screw you engineering work! I'm gonna learn the ************ outta you if it takes years!!! (haha sorry for that crazy rant)