I completely fell of the wagon yesterday

[Goonitsfree]

The past 4 weeks have been going great, I’m always under calorie goal and lost 1 stone.
Yesterday I met friends for drinks, drank FAR too much, ate rubbish and finished the evening with takeaway chips.

A rough estimate on MFP puts me around 1500 over calorie goal, is there any way I can bring this back and still get a loss at the end of this week?

I feel bloated and guilty today it was NOT worth it!

I'd say that the best strategy is to say "well I enjoyed that day, back on it today"
Don't beat yourself up or try to restrict calories more than you have done already, it can become a vicious cycle if you attach too much emotion and judgement to it now. We all have off days. Good luck!