It sounds silly but I quite literally had to shovel myself out of bed this morning. My bones and joints feel like they're exhausted
I don't mentally feel tired, it's just my body. It feels like it's telling me to sleep and rest.
For background, I get a very good amount of sleep every night. This really surprised me, feeling like this, because I'm very much a 'get up and get on' person. Yes, like everyone I'd have the odd 'I'm just too cosy to move', but this was completely different.
I'm home now and just collapsed into bed with DS 
Could it be flu without the symptoms? My body feels done!
I've not had a single flu symptom but I do currently have conjunctivitis, which is probably coming to the end now as I've had it a while.