How to remind yourself that you can be hurt when feeling invincible?

first of just to clarify my psych currently thinks I am in a mixed state and i have been diagnosed with schizoaffective disorder. I'm currently feeling very invicible and impervious to harm while at the same time wanting to feel pain etc. as you can imagine this is very dangerous as I get moments where I want to walk out in front of cars or jump off buildings etc. how can I stop myself from doing this and reduce these urges? Thanks in advance.