You aren’t eating right as you claim you did. Simply, you could be eating way too much. We are terrible at estimating what we are eating in a portion; in fact, we are terrible in understanding numbers in general. So don’t judge a portion size by feel, measure it as you can. Putting food on smaller plate has been proven to lower the food we eat.
Often it is also difficult to be honest to ourselves. Keep track of everything you eat. That salad you eat might have a dressing with more calories that you thought, even contain bacon bits. Keep a journal of the food and exercise you did daily. So start calculating your calorie intake and outtake, then suit your meal to your lifestyle. If you exercise too much, you might subconciously eat more due to exhaustion, so keeping it tracked down is a good incentive to not eat more than you should. Your goal should be to burn more calories than you are taking in.