Sharing a bit of my own fever symptoms, too, if that's okay!
(Fevers between 100,4°F and 104,9°F)
Usually, my fevers make me feel very, very cold, but I don't let myself get a lot of covers because the cold is a consequence of how hot my body temperature is. So if I use a lot of covers, I will only get my body even warmer, which will worsen the fever. I usually use cold towels on the forehead or neck. (At least, I've been teached those things all my life, don't take my words as professional advice, I'm just sharing my own experience)
I personally never had a boost of energy. Fever always leaves me extremely tired, without appetite, with a headache (especially the temples and behind the eyes), shivering, weak, and usually nauseated. I usually depend on someone else to help me do most daily stuff, even a little.
My emotional state truly goes a bit wild during fevers. I feel the need to cry easily, but I don't think anger is a feeling I usually have during fevers (perhaps because I don't feel it often even when I'm healthy). I get clingy, perhaps because of a natural human instinct to need someone else during a vulnerable state. Besides that, I get very bored (because I don't have the energy or strength to do much) and frustrated with how uncomfortable the symptoms are.
(This is the 104,9°F fever). As far as I can remember, I've only ever had an actual delirious episode once during a fever (if it happened more times, I was too sick or too young to remember them).
- It started at night, when I was asleep. My fever went higher, and my nausea got worse, so I woke up and tried to make myself more comfortable, but my coordination was terrible, the room seemed all wrong (too wide, then too small), the lights seemed dimmer than I remembered, and I couldn't think well.
- I remember that night seemed to last days, because I checked my phone, and everytime, it had absurd numbers that went higher than 24 hours, or that made no sense comparing to the last number I checked (like going back a few hours or show that it was day, when it wasn't).
- I also remember being so out of it that I talked to myself, thinking someone was with me (I didn't see anyone) for some reason, and I didn't even think of calling for someone in the house.
- Other memories were lost on me because of how sick I was, but I remember being so, so distressed and confused that I cried during it, because I knew something was wrong, and the delirium symptoms just kept coming in waves and not letting me sleep. It was one of the most scary feelings I've ever had in my life, because it felt like being trapped in a weird time loop of nausea, weakness, hallucinations and confusion, without being able to even sit on the bed or call for someone.
- (I'm pretty sure I had a lot of fever dreams because I kept waking up and going back to sleep with how sick and tired I was, but the thing is... I couldn't tell when I was awake and when I was asleep. The delirium made it all seem like one thing, so these symptoms I've described could be real life or fever dreams, but it felt like all real to me, and I remember them clearly as a memory. So you can make a feverish whumpee think something happened, and caretaker being like, "ahm, I was here the whole time, whumpee, that didn't happen")
So yeah, those are the things I remembered about my own fevers. I just thought it would be okay to share them, too. Fevers can be a bit different for each person, especially depending on WHY you're having a fever (an injury infection, a virus infection and what type, heat stroke, medications, etc), so the most experiences you read, the better you can write a feverish whumpee :)