Does anyone else alternate between being a happy/"normal" person, going about their everyday activities and having thoughts of SI and/or death?

Today I was sitting in a conference, learning about different research that is going on at my university (something that I love), and I suddenly found myself feeling anxious and thinking about SI. Granted, I was in emerg twice this week getting stitches so that also might be why it was on my mind.

I find this happens to be a lot though... feeling great one second, and then being consumed by these thoughts.

Anyone else?