Even though you used to go without food for dangerously long periods of time, you can no longer do that. Your body is now accustomed to you taking care of it, so trying to go several days without food will make your body freak out. You need to take it easy.
Yes, God noticed that you were intentionally trying to spend your weekend praying and fasting for the victims of sex trafficking. Yes, He saw your heart and your willingness to sacrifice this part of your life to rely on Him more desperately and show Him that you agree with Him that this is an issue worth taking a stand on.
I know that you figured that God would keep your body safe while you fasted. And yes dear, God will take care of you, and yes, I'm sure God knows that you would like to go longer than your body will let you because you take everything to the extreme. But you have to understand that you are still a human with a human body that needs food to keep it going. Running your car into the safety pole at the gas station was a sign that your brain needed a bit more power than it had at that moment. You needed to eat. Actually you needed to eat before you wiped the bright yellow paint from the pole onto the front of the brand spanking new car that your sweet hubby just got you.
In the future, if you intend to fast, make sure that you are not loopy before you decide to get behind the wheel of a motorized vehicle. Yes, when fasting, you should expect to feel hungry and maybe even a little weak. But if you're lightheaded and falling over, EAT SOMETHING!