If the test button trips the GFCI when the breaker is ON the GICI is working
If the breaker is a Trip-o-matic then either there is a short (hot to neutral) over load (Too much stuff plugged in) or the breker is bad
Some breakers are designed to trip if you touch them.
UNPLUG everything. see if the breaker holds. then start plugging stuff back in one item at a time.
True story
Camper (Nice Class A) half his outlets were out.
I ask if he had an inverter (he did not know
Had a nice Tripp-Lite
Viewed from above the breakers looked like this \/ Made 'em look like this // and all was good.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times