Dieting will reduce the amount of energy that your body has to spend. It will decrease your lifts as well and you can generally feel a bit weaker.
Try dieting in a way that you're doing a slow but controlled fat loss like Scott suggests for cuts.
a good 250-400 calories under your maintenance. I suggest you get into the mealplan page in order to get a better idea of what your diet should be like.
If you're building muscle and decreasing fat you might not be able to notice a weight diference. I know I once did a 3 month program and was stuck at 82 kgs the entire time while I was getting leaner and building a LOT of muscle. It really is all in the diet, particularly for fat loss.
You can lose fat by burning more calories than you eat, which is why cardio tends to help because you're burning more. However, if you're not under a controlled diet, you're just going to make up for those calories in cravings or eating more than usual and balance yourself out for maintenance again. That's how our bodies work.
I would suggest actually tracking your diet and keeping yourself honest. You may not be noticing a lot of change but I swear to God if you're dieting and working out 6 times/week you are making progress. I would also suggest you be more effective in your workouts. Take less rests and try to cut down to 1:00-1:15 of working out/day as that is more optimal for natty lifters
Just get on a diet, open up a spreadsheet and legitimately count your macros. Everything that goes in your mouth goes on the spreadsheet except water.
At least that's what has worked for me and I think for most people.