It's not just feeling tired all the time....

http://www.name-us.org/MECFSExplainPages/SymptomsLists.htm


Neurological/Cognitive Symptoms●Easily confused
●Slow information processing
●Difficulty retrieving words
●Occasional slurred speech
●Occasional dyslexia
●Difficulty with mathematics
●Easily distracted
●Forgetfulness (primarily short-term)
Attention deficit
●Inability to focus vision and attention
●Inability to cope with fast-paced tasks
●Overall feeling of "spaciness" or "brainfog"


Motor Disturbances:
●Loss of muscular coordination
●Muscle weakness
●Muscle twitching
●Loss of balance and clumsiness


Overload phenomena:
●hypersensitivities to light, sound motion, odors
●Inability to block out background noise and focus on on conversation
●Informational overload with inability to multi-task
●Motor overload, with staggering and weakness
●dizziness
●numbness
●tinnitus (ringing in the ears)
●nausea
●shooting pain
●Overload may cause temporary immobilization


Immune Dysfunction
●A general ill or flu-like feeling, more frequent in the acute onset stage of the illness, less frequent in the chronic stages, most notably post-exertionally
●tender lymph nodes
●recurrent sore throat
●new food sensitivities
●new chemical sensitivities
●hyper-sensitivity to medications and their side-effects
●allergies

Sleep Dysfunction
●frequent awakenings
●nightmares or agitated dreams
●non-restorative sleep
●variations in sleepiness and energy throughout the day
●hypersomnia (excessive sleeping)
●Restless legs syndrome
●periodic limb movement disorder (jerking or twitching during sleep)

Pain
●generalized muscle pain
●new onset headaches
●aching, burning shooting pains anywhere in the body
●fibromyalgia is a common concurrent syndrome with ME/CFS
●arthralgia without joint swelling
●Veteran M.E. practitioners sometimes noted that pain is most frequent in the upper spine and neck area
●abdominal pain


Post-Exertional Malaise and Fatigue
●Flu-like or hangover feeling following minimal physical or mental exertion, sometimes immediate, sometimes delayed several hours or a day or more and associated with immune activation, with sore throat, tender lymph glands, general malaise, increased pain and cognitive symptoms
●Feeling worse after exercise, rather than better
●Taking a prolonged time to return to pre-exertional function level
●Lack of endurance

Autonomic Manifestations
Orthostatic Intolerance:
●Neurally mediated hypotension (NMH) i.e. problems with regulation of blood pressure and pulse, especially when standing still; with symptoms of dizziness, lightheadedness, slow response to verbal stimuli; an urgency to lie down
●Postural orthostatic tachycardia syndrome (POTS) i.e. Excessive heart rate during 10 minutes of standing still; blood pressure drop upon standing; lightheadedness, dizziness, nausea, fatigue, irregular breathing, visual changes sweating, headaches.
●Delayed postural hypotension i.e. blood pressure drop after many minutes of standing, rather than upon standing
●tilt table test abnormalities


Other autonomic manifestations:
●Palpitations with or without cardiac arrhythmias
●24-hour Holter monitor results with oscillating T-wave inversions and/or flat T-wave
●breathing dysregulation
●shortness of breath
●intestinal irregularities
●irritable bowel syndrome
●diarrhea
constipation
●alternating diarrhea and constipation
●abdominal cramps
●bloating
●nausea
●anorexia
●urinary frequency
●painful urination
●excessive urination at night
●pain in lower abdomen

Neuroendocrine Manifestations
●loss of thermostatic stability (fluctuations in body temperature; fluctuations of cold and hot in different parts of the body; intolerance to extremes in air temperature; low body temperature)
●night sweats or other sweating episodes
●weight change, with loss of appetite in some patients or abnormal weight gain in others
●worsening of symptoms under increased stress (physical or emotional)
●loss of adaptation to situations of overload
●anxiety

This is the most complete and most easily understood list of symptoms that I've found on the internet.  The other list that is pretty complete is the Canadian CFS/ME diagnostic manual.