Boosters disappear

Sometimes I manage to win a reward in the game -jokers or extra cards for instance but they always disappear almost directly...if  i use them in the next level they are there but I can't save them fot the next day or longer.They are all gone when I could have needed them,..This has happened many times and it is tiresone and frustrating.  Are boosters that you have won only valid the next round or are they supposed to last a little longer...