I feel so exhausted and I've done nothing woke up this morning with my back killing me like I was…

I feel so exhausted and I've done nothing woke up this morning with my back killing me like I was standing all night in one place then I took a nap and when I woke up I've been feeling nauseous since then I've also just been feeling super exhausted like my body feels like I just ran a marathon I don't know what's up but its not cool :(