No,you aren't the worst gambler (for now). You made a good decision to stop even though you already lost your 10 btc and still hold the rest (15 btc).
You and we always have the reason why you/we must continue this live, there are still your parents, your brother & sister, wife and your children (if you already got married).
Here is an example of a gambler worse than you, he lost 360 btc just in some minutes...
For every action, there is an equal and opposite reaction.
Unlucky for bettor, but really nice for investors. I believe house profit is possibly the highest it's been during the latest version, but don't quote me on that.