You're trading fat for muscle. Muscle weighs more than fat which explains your slow weight loss. I'm in the same boat as you. I took shirtless pictures day one of my winter workout and have lost very little weight over the past two months. My pictures now show that my routine is working as I'm much more defined and I've lost inches in my midsection.

Keep up the hard work. You may want to take in more clean calories to reduce your defiect some to see a quicker fat loss but slower muscle gain. Just my .02