My OH has been working away for the last 5 weeks and comes home on a Friday night leaving again on the Sunday, so I know exactly how you feel.
Just remember that as he is not there, he will notice you shrinking. (My OH has noticed there's less of me!). As your OH is not seeing you every single day, he will notice changes.
Night time for me is worse as you are alone. That bag of crisps or biscuit or whatever is shouting on me. I try and keep most of my points for night time and have a large fruit salad, yogurt, alpen light bar and a cup of coconut chocolate options.
Be strong, it'll be worth it. That little devil that's shouting on you will soon get fed up x