I'm losing weight but I fully overate yesterday, how can I make up for it today?

I have lost about 1kg so far in the past few weeks... Maybe 2kg. I have been burning around 300 calories at the gym each day and restricting my calorie intake to a healthy amount to lose weight. But yesterday I had a healthy breakfast and lunch but then had this creamy alcohol drink (cocktail drink) and then we went out to this fancy restaurant in which I had a creamy chicken and mushroom crepe, fries, cheese bread and dessert (including cream and ice cream and waffles all in one!). I'm going to the gym soon and haven't had breakfast yet (it is 10.21am). Should I work extra hard at the gym and restrict my calorie intake to an even greater extent or what? Because I really want to lose about 3kg more in 3 weeks. Please help. Thanks!