I am also a fairly new PPL and for some reason I always get apprehensive everytime I fly solo. All the way through my checks and just before take off the old butterflies are in the stomach, but once I'm in the sky I seem to settle down. I think its because when I'm on my own I consider all the 'what if's?" - e.g what if the cloud suddenly surrounds me and the visibility plummets?
However, when I take passengers I'm absolutely fine because I put every thought and effort into making them comfortable and happy and making sure they have the confidence that I'm not going to kill us all.