Do you recognise these symptoms?

[Askil]

I had a diagnosis of fibromyalgia 4 yrs ago and it is well managed through exercise and Pilates and Yoga.
last yr, after a lovely day & whilst watching TV, I suddenly started to feel awfully chilly from deep inside spreading all over outwards. I started violently shivering (teeth chattering) which Paracetamol couldn't touch. The central heating was on.

I took to bed as by now i was aching all over, flu like aching not the usual fibro ache which i can distinguish. Whilst i was shivering in bed and i kept having this uncontrollable urge to stretch my legs and arms.
DH made me a cup of tea which i managed to sip. Gradually the shivering subsided and i fell asleep. When i woke up in the night, it felt like the 'fever' had broken. I felt clammy & light-headed but all the aching had stopped. I felt like I had just recovered from a terrible fever.

The cause was unknown.

2 Months later another attack happened in exactly the same fashion. It came on suddenly for no reason. I had a very hot cup of tea which calmed the shaking and went to bed. In the morning i felt warm and clammy & light headed as if recovering from a bad fever.

I visited the GP who said they cant do anything as I was not ill when I visited the GP. I was asked to call when I'm actually ill, which I can't as it always happens out of hrs and you can't get through to the GP anyway.

It's happened 3 more times after this with all the same symptoms. During the last attack I had I thought i was going to tear a muscle in my back from the continued stretching of my arms and legs. I was blue-lighted to hospital where i was kept in for the night for observation, but eventually, everything came back normal.

I do not have restless leg syndrome.
It always happens at night, it's never been during the day and mysteriously starts to reduce after a hot drink. After sleep, the fever seems to break and the temperature comes down.
I have not been eating cold things or drinking cold drinks.
I'm not on any medication.
When I've googled, Sepsis comes up but it all seems a bit inconsistent with how the attacks start and go away.

I'm starting to get really anxious and hoping someone might recognise some of these symptoms. Thanks.

I have got a new thermometer to monitor my temperature.

I don't think it's low blood sugar as i don't seem to have any of those symptoms described on the NHS website. The shivering is fever-type shivering (the type you get with Malaria) unlike the 'jerking' you get with seizures (very familiar with seizures as DSIS had them for 2yrs)).

I have a history of low blood pressure although it has never caused any problems but I'm going to start monitoring that as well.

Thanks all.

Nothing related to these episodes but the restless legs sometimes can be caused by being ‘short of something’ like iron/magnesium if you can get a multivitamin that might help.

Just to add, not menopause as i had a full hysterectomy some yrs ago, so post menopause (thank fully!).