When I think about fatigue specifically I can think of many forms of fatigue each one comes with its own set of instructions.
There is a difference between being tired and being exhausted or lethargic, let me explain;
Tired-
This is the most common type of fatigue and I experience it most of the time. I am always tired because I am always lacking sleep or in need of more sleep. This kind of fatigue doesn't incapacitate me but it can make me sleepy or irritable.
Exhausted-
This kind of fatigue is a little more pervasive but I reserve this definition for the kind of tired that comes from working physically or mentally hard, it's fatigue that for me makes the most kind of sense. Exhaustion is feeling like you are tired from head to toe, brain to bones. If I worked out or did chores or a project, this is the kind of fatigue I expect to feel. However, sometimes I can become exhausted easily. It takes very little hard-work to cause exhaustion. when I reach exhaustion I must rest, where if I am simply tired I can keep pushing through. Sometimes a quick rest will be enough other times I need sleep. I would say I reach exhaustion at least once a day, if I'm lucky it's at night after everything is done, but I'm not very lucky normally.
LETHARGIC-
This kind of fatigue is the most frustrating because not only am I tired and exhausted, no amount of will-power can allow me to push through. When this kind of fatigue hits I am incapable of action, I can't lift my arms or legs they feel like lead weights. Even my tongue is too fatigued to move and I often slur or whisper words if I try, sometimes it's all I've got just to nod or move my eyeballs. This kind of fatigue doesn't usually have a build up either it just hits me. I know there are triggers like excessive heat or cold, perfumes, hunger, or over doing it. The biggest one is not sleeping or getting up too soon, that will almost guarantee a lethargic response sometime during the day. It feels like gravity has doubled, like you feel on those centrifugal-force rides where you get sucked to the backboard while spinning in a circle and you can't lift your head or limbs. This kind of fatigue is devastating. The worst part about it is you don't get time to get to a comfortable place. If I'm at a doctors office or driving somewhere or shopping and I feel this way I will get stuck. Like making it to one side of the mall and knowing you can't make it back. Like driving and knowing you can't make it home. At one point in time this was happening to me several times a week sometimes even daily. It still happens a lot but since I have changed my schedule to allow my sleep to come naturally and stay asleep until I wake up naturally I have had fewer episodes.
I know now that I need certain things to keep my fatigue at a more manageable level. I need to eat regularly and keep snacks very near by in case I have a drop in blood-sugar. I need to keep my exertion levels low and do a lot of "pacing" practices. I need water. I also absolutely need to stay in bed until I feel ready to get up (that is the most inconvenient one but the most important one) if I get up too soon I'm almost guaranteed to crash.
Everyone one of these levels is complicated by pain and other fibromyalgia symptoms. A person can generally push through a pretty significant amount of pain but add fatigue to that and there is nothing left to fight with, if your battery is drained you have no power to operate.
There are days when I know that even microwaving food won't happen and if it isn't available to me in an instant form than I will not be eating, that is awful. I have learned to keep protein shakes or granola and yogurt or some other form of high energy food on hand always.
I know that people use these terms a lot but I think most people, thank goodness, have no idea what true fatigue feels like and we are always going to have trouble helping others understand the extent of our "tiredness."