I need my motivation back

Hello MFP!

Since the weekend I'm finding it really hard to get my motivation back (I went to a beer festival and drunk a lot of beer and ate badly). I'm fine if I am at home and cook lots of healthy meals from scratch and don't feel hungry but if I am honest I am finding it's hard to have a social life and stick to the 1200 a day cals or with the extra cals I 'earn' through exercise. I've managed to lose 12 lbs in 9 weeks and want to lose 21lbs more. I'm finding I can't eat out, drink alcohol, or at friends (unless I control what they are cooking!) as otherwise it goes pear shaped despite my good intentions so has put a damper on my social life. I also get invites to eat out as part of my job for work (I'm a food publicist). I need to keep telling myself it's only for 3 months more months to **** 21lbs. Must get back on it - kind encouragement appreciated!