Follow your heart, first. I graduated in Physics, went to work at Savannah River Plant in 1972, a year where PhDs wound up driving taxis. I started as a Reactor Supervisor and 4 years later was a Reactor Physicist. I also Picked up an MBA along the way.
Moved out to Hanford and started writing Procedures for the restart of the Old Plutonium Uranium Extraction Plant (PUREX).
After 9 months, I became the Senior System Designer and was writing Corporate Departmental and Emergency Procedures. At this time, I became involved with starting a Procedures Group within the American Nuclear Society, this evolved into The Human Factors Group of the ANS. I chaired the Group as Organizing, Chartering, and first elected Chairman. I also began my studies with Don Farr and Alan Swain of Sandia Labs in ergonomics. I left Hanford after being offered an consulting job with NUS Corp. supposedly to set up a Human Factors consulting group. Instead, I got caught in an internal turf war and the position lasted 3 weeks.
Setting out on my own as a Human Factors Consultant, I eked out a living for about a year, when I was offered a Position as Safeguards Inspector with the International Atomic Energy Agency. Interestingly, here it was not my physics, But my MBA that proved of most use. Yes, I did Gama Spectrography, Isotopic analysis, and a lot of quantitative and qualitative analysis. But my major activity was accountancy, something all the PhD physicists and engineers were ill equipped to accomplish. So I let them do their thing and I balanced the books! During Safeguards Inspections in Japan and Taiwan, The facilities were shocked when some one actually audited their books and pointed out systematic accounting errors in their books! I filed 312 accounting discrepancies and 3 anomalies. A discrepancy is an official report of an error or failure. An anomaly is reported to the UN Security council and must be answered in that forum. My fifth year was spent writing a major statistical computer program to analyze variations in the amounts reported as shipped and received between Plants and countries.
When I returned to the states, I worked for the Navy for a time refueling submarines.
Think you can make a living with a physics degree?