You check your phone, and it's 2:02am. You're meant to get up in four and a half hours, but your mind's racing with hypothetical arguments, memories of stupid stuff you said three years ago, and what could possibly go wrong at work tomorrow.
Yep - when your body is exhausted but your mind is very, very much awake - it can be pretty infuriating.
But besides burying your head in your pillow and repeatedly saying 'go the fuck to sleep' to yourself, there are a few things you can do to get yourself some shut eye.
1 Switch off your screens
Some believe staring at blue glowing screens right before bedtime can 'confuse' our brains, and trick us into thinking it's wake-up time.
Though evidence of this isn't totally 100% solid, shutting down your computer and phone in good time before you sleep makes sense anyway.
Ever find yourself frantically scrolling down your Facebook news feed when you should have switched it off half an hour ago?
2 Try mindfulness
Mindfulness can sound like a trendy smug-fest, but really, it's all about taking a breather and reflecting.
You can start off by practicing mindfulness for 10 minutes a day, and the idea is that your mind will be calmer and less full of conflicting worries.
3 Write your worries out
The human mind is strange. However impossible it may seem to soothe your worries, writing them out on paper just... works sometimes.
Keep a pen and paper by your bed, and write down what's stressing you out in not too much detail.
This works because A, it's cathartic and B, you can look at those worries in the morning with a fresh pair of eyes. You'd be surprised how much smaller they seem after some rest.
4 Do (a bit of) exercise
Firstly, ignore your friends doing half marathons every other weekend. Ignore the yogalates-every-day-after-work lot, too.
Doing a little bit of exercise now and then, at your own pace, can make a huge world of difference to your sleep patterns. Especially when you're stressed and tense.
It may be the last thing you want to do when your life's hectic, but go for a ten minute jog - well before bed so you're not rushing with adrenaline - and notice yourself feeling more relaxed when you hit the hay.
5 Ditch the flat whites
They're so goddamn tasty... but so goddamn sleep disrupting.
The effects of caffeine can last for up to 24 hours (oh, great) so it might be best to avoid it altogether, or at least in the evenings.
Instead, get yourself an elaborate selection of herbal teas - give Twinings a run for its money.
Or hot chocolate, if that's your vibe.
6 Don't eat an entire Domino's Two For Tuesday before bedtime
Don't stuff your heart out just before you go to bed, because admit it - it's hard to sleep while feeling uncomfortably full.
7 Don't go to bed smashed
When life is stressful, all you want is a couple of (ten) G&Ts after work.
But lay off them a little, yeah? Because according to Drinkaware, even a couple of drinks can interfere with your normal sleep process.
If you get smashed right before bedtime you can go straight into a deep sleep too, which means you'll miss out on the usual first stage of sleep - rapid eye movement (REM) sleep. Which isn't a good thing.
8 Ditch that goddawful rented mattress
99.99999% of people our age (source: unverified) live in crappy rented accommodation.
But one thing we shouldn't have to deal with is the back-breaking mattress that comes with it.
A wise saying goes that you spend a third of your life on a mattress, and it's true. They may be expensive, but try to put some cash aside for a decent one - it can be pretty life changing.
Feature image: iStock