season finish and now what??

ok season finish tonight ...
so and now what???

when the new one starts ??? we have rest days or something??
also my player will lost stars???

Next season is Tuesday, normally. Your players will lost one star, but will keep their strengh.

lost stars but not quality

your players will only lose one star if you are promoted to the next level

New cup competitions start tomorrow and the new season begins with those, champions league and league won't start until Tuesday.

Regarding your players, they will stay the same quality, but stars are a measure of their quality for that level. So a 5* player at level 1 will only be a 4* player at level 2, even though his skills are the same.