Thank you so much for your words!
The pictures are real, and so is the fact that I exchanged them with strangers. And you know what? After doing it for a while, it started feeling really natural. It became more and more comfortable, and I also loved the reactions that people had when they saw the drawings and made a connection with the creatures I came up with.
I guess knowing that I have something to offer (even if something as small as a drawing) when I approach someone makes me feel more open, because I subconsciously expect to be accepted. And more often than not, I really am!