Am I taking on too much?

I have to admit I am a bit scared. Don't get me wrong I am very happy and excited about my new job starting soon. What I am scared about is that not only am I going to be starting a new job and learning lots of new things, I am also going back to school and taking not one but two classes online at the same time. I am scared that I am going to get overwhelmed and lose control. I will be going from unemployed and taking a long break from school, doing not much in the way of learning anything to working on learning 3 new things at once. I am working really hard at keeping up with healthy eating and working out regularly. I don't want to get overwhelmed because the first thing to go is usually my workout. Then my healthy eating will be out the window. I am going to do my best to take things one at a time.