I feel like this most of the time too... I went for about 10 years without crying, and honestly thought i couldn't physically cry. Even when things were really bad for me and i really wanted to cry, i just couldn't do it. I think it's because i usually keep my emotions to myself, and i've got so used to being this way that i find it hard to cry, even when i'm by myself. However, my cat died a couple of months ago, and i cried few times then... I surprised myself then by being able to cry, but it made me feel a bit more human i guess lol