Fiat Punto gears no longer go in ….coupling or what?

Moin Moin, yesterday it happened just within the first 10 meters driven Achha that the gears could not get in again? That was only possible with considerable effort. I could still switch into the third and fourth gears, but also only with resistance. In the first and second I could not switch at all, although I could put in the second a few times. Sometimes there was hardly any resistance to feel, but that was rare. I still had to start in the second or third gears in the stand with inserted third gears the engine is not strangled. Whether it would roll off without a brake on the hit clutch I did not test, and since I could only drive in the third gears I could not notice anything like that either. When the car was standing and the engine was out I could insert all gears without problems. After that started again, the problem occurs only with running engine, regardless of whether you drive or stand still circumstances. Does anyone have any idea what this could be and what a repair would cost? And what would I be afraid if I just continued driving so well it could be done under the next time of the brake.