Fallen off the wagon - big style!

Hi all, after losing 6 and a half pounds veeeery slowly (6 weeks) I've been away with work for a week and have lived off hotel food I.e 3 course meals, wine etc. Whereas I said no to dessert and ate lots of fruit and healthy options I feel totally demotivated having got back and put on 3lb.

Any tips on how to get back on track? I've lost all interest in the diet and the gym