The mistake is often expecting yourself to feel normal all evening. You probably will not for a while. Give the night some structure so every empty hour does not become another opportunity to check, replay and spiral.
Split the evening into three smaller jobs.
Something for your body. Something that occupies your attention. Something that helps you wind down.
Your body might need food, a shower or a walk. Your attention might need a game, a film, a book or somebody to talk to. Winding down might be ten minutes of journalling and getting your phone away from the bed.
Make the room less irritating.
When your head is already loud, small environmental problems become surprisingly annoying. If outside noise is genuinely keeping you alert, Loop Quiet 2 earplugs (affiliate link) on Amazon are a small intervention rather than an entire sleep-tech purchase.
Give yourself comfort without pretending comfort is treatment.
A blanket, warm drink or familiar programme is not going to heal heartbreak. It can still make an unpleasant hour easier. If physical restlessness is part of the problem, a weighted blanket (affiliate link) on Amazon may feel more settling while you read or watch something.
Protect the last hour from new information.
The worst time to discover a new photo, story, follow or message is five minutes before you want to sleep. If checking their profile reliably changes the whole direction of your night, stop giving yourself access during the final hour.
Put the phone somewhere you have to physically get up to reach. Write down anything that feels urgent. If it is still urgent tomorrow, it will survive until morning.
If your whole sleep-wake rhythm has drifted, work on the morning too.
Staying up until 3am and then sleeping through half the day can make the next evening harder again. A wake-up light such as the Lumie Bodyclock (affiliate link) on Amazon is the more expensive option and only makes sense if you genuinely want help rebuilding a consistent wake routine. Do not buy it just because tonight feels bad.