You have been thinking about this for three days.
The problem has not gotten smaller. It has gotten larger — because each hour of thinking has added another layer of analysis, another contingency, another scenario that needs accounting for. The original problem, which was manageable, has been thought into something enormous.
This is not what thinking is for.
The Vedantic tradition distinguishes between three functions of the inner instrument: Manas — the reactive, associative, sensory mind that processes input and generates endless commentary. Buddhi — the discriminating intelligence that can see clearly when it is not overwhelmed. And Prajna — the deeper wisdom that does not think its way to answers but recognises them.
Most of what we call thinking is Manas activity — reactive, circular, loud. It produces the feeling of cognitive work without its substance. It is the mind running on a treadmill, expending enormous energy while going nowhere.
The answer you are looking for is not at the end of more thinking. It is in the gap where thinking stops and something quieter speaks.
The great decisions of your life — the ones you look back on as correct — how did they feel when they arrived? Usually not like the product of analysis. Usually like a recognition. A clarity that appeared after you stopped pushing.
Archimedes did not solve the problem of displacement by thinking harder in his study. He stepped into a bath. The solution arrived when the Manas was occupied with something else and Prajna had space.
The practice is counter-intuitive: when a problem is most urgent, stop thinking about it for one hour. Walk. Sit in silence. Do something with your hands. Not to avoid the problem — to let the deeper intelligence engage with it without the interference of the reactive mind.
Thinking is a tool. Like every tool, it is most effective when you know when to put it down.