[villagetinker]

OP, there may be more than one GFCI in the garage, our house has 3 of them. Double check all of them. There will be 2 buttons, one labeled TEST and one labeled RESET. Push the TEST first, then the RESET. You should hear a click when the GFCI resets. If you do not hear a click, the GFCI did not reset, check the breakers (see below). Try plugging in a known good lamp to confirm the GFCI is working.
Yes, circuit breakers do occasionally go bad. When you reset the breaker, make sure you move the handle all the way to the OFF position, and then on the ON position, you should hear and feel a click as the breaker closes in to the closed position.
As noted above, if you got a lots of water in an outdoor outlet, it may be so wet that it is tripping the GFCI immediately.
Also, your outside Post lamp is on a GFCI, which might be the same GFCI as the outdoor outlets. There have been many problems reported with post lamps. NOTE: if you post light is working, this is not the problem.
Send me a PM with your phone number and I will try to give you additional help.