Lee - driving truck is a second career choice for many. As ntimevan mentioned you should really research prior to making the decision. Many variables affect success and happiness with driving as a career choice. Perhaps apply to a number of expedite and traditional truckload carriers to find which will accept you. Then research what their driver requirements are, such as how long you are expected to stay on the road, when and how many days off you are entitled to, what benefits (if any) are offered, pay, and how this new income will affect your Fire Department pension or retirement plan. Talk to some of the drivers of the carriers you have narrowed your search to.
Hope this helps.
Thanks,