Ben Affleck is back on daddy duty following some hard partying last weekend at a Halloween party where he was seen stumbling to get in a car with his new girlfriend Katie Cherry. The actor dropped off his two younger kids at school, on Tuesday, after telling paparazzi the day before that he wasn't going to let one slip-up get in his way of his sobriety. Good for him!

But a new report claims friends are worried. The Unicef Halloween party where Ben indulged, had an open bar and Affleck was all over it, drinking "clear liquid" -- either tequila or vodka, according to an eyewitness. Us Weekly reports that those close to Ben are worried: "The people who care about Ben know where this is headed. If he doesn’t get help, he won’t be able to stop," the mag attributes to a source.

After the party, the pair were seen at a casino, according to the report -- gambling being another of Ben's addictions that, sources tell us, he has never gotten rid of. Affleck's a regular at weekly poker games with pals like Leonardo DiCaprio and Tobey Maguire where there are plenty of temptations, including women.

But Ben swears this won't "derail" him. We hope he's right!