I'm sorry to hear that you are suffering from headaches, fatigue, and foot drop. Without an examination, its difficult for me to say for sure what is causing your symptoms. Nevertheless, I can provide information regarding testing that should be performed in your case. First of all, foot drop can be caused by a number of different issues. For example, vitamin B12 deficiency, Lead poisoning, compression of the fibular nerve by lying in bed for prolonged periods of time, syphilis, etc.
I specifically want to highlight the lead poisoning, because it is the diagnoses that most of us neglect to consider in this type of case. Lead can be consumed accidently through contaminated water, or food. Lead poisoning usually causes headaches, dizziness, GI symptoms, and neurologic symptoms like foot drop.
I would recommend that you request that your doctor test you for vitamin deficiencies, and toxicities (i.e. Lead), and perform and electromyography which tests the function of the fibular nerve.
Please let me know if I can answer any questions for you.