When your brain runs about some issue over and over again and won't stop, just like a hamster running in its exercise wheel. It keeps running, but doesn't get anywhere.
I'm having such hamster wheel brain about whether or not to take this job offer.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".