I´ve done sit ups for 2 months and after I stopped my belly became 'bigger' not because of fat but I feel as if the abdominal muscles grew and then became loose. How can I revert this ? I dont want to do more sit ups in case the muscles grow even more , I just want to have my belly as it was before, not strong but flat. Is there any way of making the loose muscles disappear?

thanks for your help