Feeling unmotivated...

So I was all hyped up when I first downloaded this app and I was doing mostly good for a week or so but then over the weekend we went to a shindig and I let myself go and indulged myself, and rightly so cause everything was so fancy and tasted so good and I don't know when I'll go to something like that again. Anyway ever since I haven't been very motivated to continue my diet. I try to gather up the effort but can't seem to. I forced myself to run a little a few days ago. I really really want to stick to this this time. Maybe if I sleep more I'll feel better and more refreshed..