Wondering just how much muscle gain is impacting weight loss

Dear James, Daniel and Emily,

Here's the thing, I made a plan at the beginning of the year to lose some more weight. I chose to do this by doing 2 things. First, reset my Lose It application on my phone, and set up a goal weight with daily calories intake etc. Second, set up a pretty ambitious new training schedule: running 4 days a week, with 3 days of strength training (push ups, sit ups, knee bends).

Initially that worked well, a couple of pounds washed off. Then the cold snap hit and I wasn't able to stick to my running program, and subsequently had a harder time hitting my net calories. Not a problem I though, once I can resume my training as a regular habit I should be able to get back on track with the weight loss.

Well that has not been the case, I have had 2 good weeks in a row now, with net calories coming in below my goal for the most part. Especially this week, I was really good since my running distance increased. And I have even found a decent balance as far as the cursed evening snacks. And yet the weight is stuck in a plateau.

Now I now these plateaus happen, and that the best strategy is to just hang in there, be patient, keep up with what I have been doing, and the weight comes off. But the question that is nagging in the back of my head is this: I now I have been building muscle all this time, I can see and feel this. And I know I can do more physically then I would have even thought a year ago when I was at roughly the same weight. What if everything I have built up is actually resulting in some of that increased weight (since muscle is denser than fat)? What is the best way to find this out? Because I don't want to start beating myself up every week over my weight not going down, when by all measurements it should have decreased.

This is just what is going through my head today. I am not going to let it really get to me, I will keep counting the calories and burning whenever I can. This is just something I will be looking into, and if anyone reading this cares to comment feel free.