Fever you need to sweat to break it out.
Bundle yourself up, and just wait it out. Eventually, you'll break a hard sweat, and once you do, wait about an hour, then take a hot shower.
Keep yourself from drafts, and stay away form air conditioner vents!
That same night, bundle up with a heavy blanket to sleep, the harder you sweat the better. This always works for me with a fever I cannot bring down.
The weakness is dehydration, same with the cramps. For that you need Gatorade. NO substitutes!!! Drink it in small sips, as much as you can hold down, as often as possible. You need a 16 ounce bottle at least every hour. Sure, you'll wee a lot, but your body desperately needs the electrolytes and sodium in the Gatorade to level out. Water is good, but you really need Gatorade.
I hope this helps you out.
Gale