i figured he meant narcolepsy, but nympholepsy made me giggle.
my 1st thought while I was reading your post was hypothroyidism(over active thryoid), you will be in my prayers and I'm hoping things get better for you quickly.
HYPOthyroidism is an UNDERactive thyroid. HYPERthyroidism is an overactive thyroid or graves disease. <-- just to clarify (like hypo for us means low BG and hyper means high BG).
my first thoughts are food/nutrition related (surprise, surprise). it could be related to dehydration, deficiency in vitamins/minerals (especially iron), lack of exercise, or a diet unbalanced in macronutrients (fat, protein, carb). have you altered your diet or tried eating differently recently? it's funny how food works - basically you will function the best when you get just the right amount of exercise and calories, but you will be tired if you get too much or not enough. generally the same idea works with other nutrients - too much or too little throws the energy balance out of whack. food and exercise are 2 of the easiest things to alter.. and don't require any tests.
make sure you are getting at least 130g of carb every day (over 200g is average for an adult). drink plenty of water throughout the day, and if you sweat a lot something like the low-cal gatorade or powerade zero will help replenish electrolytes (milk also does this, but a lot of people don't want milk after they exercise). you can also try eating small, frequent meals throughout the day as opposed to three big meals. eating constantly throughout the day provides your body with constant energy and increases your metabolism. fruits and veggies have a lot of good nutrients in them without providing a lot of calories, if you are worried about consuming too much. if you don't already, i would encourage you to take a multi-vitamin with iron every day. a lot of women are also low in calcium, vit D, and omega-3s. supplementing those is up to you.