The biggest weight gainer (unless you eat a consistent fast food diet, in which case you probably have other malnutrition problems) is the sugar intake with coffee, tea and snacks. You may be OK in your original wieght loss plan by just having black coffee or tea with no sugar. Reducing the intake over a period of time would be beneficial too.
How long had you been having several cups of coffee per day? If it was a few years, going cold turkey like that was probably one of the more painful ways to drop it, as you found out.
Additionally, if you've had a bit of extra weight for a while, your body would be 'set' to that wieght and try to maintain that weight and you have to work REALLY hard to drop below that level and then MAINTAIN that weight until your body thinks that is the new normal weight.
Cutting out the sugar may be the best immediate solution.