Like some people said, its mostly about the diet. You say you are eating "healthy" foods, but that really doesn't mean much. I can eat 4000 calories of healthy foods, you need to cut your calories even more if you are not losing weight or not losing weight as fast as you should be. The more weight you lose, the LESS calories you are burning because you are carrying around less weight.
Lower your carb and fat intake (don't eliminate either). Also try changing most your carbs to low glycemic carbs.
Change your weight lifting workout and do a different type of cardio. HIIT is also a good idea like someone already mentioned. If you have been doing sets of 8-12 reps, start doing a different rep range for a while. Either higher or lower. Also change the exercises you do and the total number sets of reps. Do more lower ab exercises, but keep in mind they won't show until you burn the fat.