How to get out of a plateau?

So, Im on my 4th straight week of healthy eating and working out like never before. I cook all but 2 of my meals for the week, I eat the right amount of calories, I use lean protein and no butter, I cut back on my carbs and I eat breakfast. I have incorporated weights into my gym routine and average 40 minutes a day of cardio, and I haven't dropped a pound. What gives?? It's not just that I havent seen numbers change on the scale (i havent gotten on one since the last time when I had gained a ridiculous amount of weight) it's that my clothes aren't even fitting differently. I know that muscle isnt taking the place of all of my fat. So today I'm going to try to find away my plateau.

I started this morning with oatmeal and added 2 tbs of flax seed. Its full of fiber and supposed to be very good for you. This afternoon I plan on mixing up my workout. Some high intervals on the treadmill and then maybe the stairmaster. I havent been doing high hintervals but they say it scorches fat, so Im willing to start it up. I'm also going to look into investing in a protein powder. There are just so many kinds that Im at a loss of what is best of me and what I want. But maybe Im just not getting all the protein I need in my diet. Could that be hindering the weightloss? I'm not sure but I am determined to get to the bottom of this!

It is nice and cool out this morning here in Orlando and the air felt so clean and relaxing as I walked into work. I brewed myself a stemy cup of coffee and added my pumpkin creamer, so it feels like a real fall day. If only it would stay well below the forcasted 89 degrees.