You don't have to solve it tonight.
These can wait until tomorrow.
The act of externalising — physically writing a worry and placing it somewhere — relieves the cognitive load of "keeping it in mind". It's a form of the "parking lot" technique used in CBT for insomnia and generalised anxiety. When the brain knows a thought has been recorded somewhere safe, it releases the need to keep rehearsing it. You're not ignoring the worry. You're just not carrying it right now.