Worried about 4 year old with hi/lo temp

[LapinDeBois]

DS2 has had a really persistent fever for a couple of days (began v late Sunday night). Has been hard to keep his temp down with Calpol, and at times it's been up at 40.1, but with cold feet and hands - but when his temp has dropped to 38.5 or so he's been pretty chirpy. Tonight I have given a Nurofen dose, and he's fallen fast asleep but temp is down to 35.5. Last night was similar, and he was shuddering with cold (but still drenched in sweat). Doctor on Monday said it was just a general throaty virus. I don't know how best to manage him. Should I now put a warm cover on him to keep him warmer - but what about when meds wear off? I'm exhausted from two nights looking after him, but scared to go to sleep in case he takes a turn for the worse. Any advice?

My dd us 20 months had fever last week I gave calpol and calprofen (baby ibroprofen?) her temp took a couple of days to come down. I took her to gp on second day as couldn't get her temp down but they says it was a viral infection. They did tell me to strip her off at night though as I normally have her in pj and grobag so I just had her in a shorts and vest at one point.
Can you take it in turns with anyone else to check or have ds in your bed?
I set my alarm to keep getting up and checking dd's temp in the night.
Hope your ds is better soon

My 3 year old DS seems to get every bug going and has the temperature spiking often. I wouldn't be able to function if I was up every night he was ill! I usually co-sleep with him when this happens and DH goes in the spare room. Then I can keep an eye on him (I trust my mummy radar to sense how he is when he is right next to me) and get some sleep. I tend to put him in just vest and shorts so he has something on and I keep putting covers off or on depending on how hot he feels. Have you got a Braun Thermoscan? It makes taking the temp so much easier and quicker. I was also told not to store open Calpol and Nurofen for more than 6 weeks or so as it starts to lose it's effectiveness.

Do you take his temperature when he's well? My DS has a very low resting temperature naturally.

Thanks for your replies. Well, I did get to sleep (with an old baby monitor turned up high) and he's just slept through the night! So hopefully he's turned the corner.