We all have our moments of weakness, so try not to be to hard on yourself! Here's my suggestion...start keeping a diary/log of what you eat throughout the day. I've heard it recommended a thousand times to help motivate a person to change their eating habits. There's a fantastic line of books for doing such by Corinne T. Netzer. There's three in all:
1) The Carbohydrate Dieter's Diary
2) The Low Fat Dieter's Diary
3) The Dieter's Diary
All 3 books give you daily space to record your breakfast, lunch, dinner, and snacks, and ALSO has room to log your daily workouts. I just bought my own at the mall, but they can also be bought online at Amazon.com, and barnesandnoble.com..both places sell them for around $8.00.