I have the heating on, 2 jumpers, extra socks a scarf and a hat and I've just jogged on the spot for 10 minutes and run up and down the stairs a few times to try to warm up. I've had 2 cups of tea in the last hour.
My body temperature is normal (I've checked with 2 thermometers). Covid test clear - only 3 weeks since I had the thing anyway so be miffed to get it again so soon. The house is 17 degrees which is as hot as I usually like it.
The only warm part of me is my hands which are usually cold 
Yet I'm juddering with cold - my teeth are chattering and I feel awful and have a headache.
Any ideas because I am at a loss?