That's not weird at all (imo). I am the same way or i'll think about telling T and I end up telling someone else because (like my best friend) because I just happen to talk to them first. In my case it's because the conversation is more purposeful when discussing those thoughts with T whereas my friends may or may not be available, may or may not get it, may or may not care. With T she cares about everything I care about (or makes me think so at least) and also she usually knows the significance of something happening more so than others.