Some people can win a huge amount as jackpota but yet the amount that they won can not be compared to how much money they have lost in entire life while gambling, can you say such person has won the casino because they won a jackpot?
Do you have record of the exact amount you've lost since you started gambling? No, right?
So yeah, you can say you've won. Even if the jackpot is not up to the exact amount you have wagered your entire life,. A win is a win and it's not everyday one gets to win sure an amount. The most important thing is to put the money to good use, so it can always remind you what you used it for.