No matter if you 'blow it' today or not, the fact that you record everything you eat and do is a start. I have been there also. I spent my whole life in the normal range of weight - then a year and a half ago, I was downsized from my job. Although I was not unhappy about it, the change in my life really changed my activity level and of course being home (with my husband also retired) I ate more. I would say about going back to the gym and watching what I ate but it never happened. I had used Fitday before the keep my weight where I wanted it so opened it up again and started recording. It makes such a difference. If you record a day that you 'blow' it motivates you to do better the next day. I'm also back at the gym most every day for classes and some weight training. My weight has just gotten back where it should be for my height but I want it down about another 10 - so not back where I was but back to a healthy for my age. I'm soon to be 54 and it really is harder to get as toned as I was but Fitday helps as I always know I am going in the right direction and that it will happen - just more slowly.
You will succeed if you record everything! Good Luck!