I wouldnt be surprised if you are retaining a lot of water actually. It is quite possible that you could have gained lean mass and lost fat at the same time if you are new to exercising. But water weight is more likely the cause.
When I took up walking (seriously like 8.6 mile trips) and weight training, I kept gaining weight. And then I cut down my sodium and bam! it all flushed out. About 6 pounds of water.