I get a lot of irrational thoughts, too. Remember that they are just thoughts. We have seriously over active imaginations, which fuels our panic like a bonfire.
You are not going crazy! If you were, you wouldn't know it. Sometimes, I think, how nice it must be to be blissfully unaware of your insanity. ;p
But seriously, just remember that these are only thoughts and because you know that they are irrational thoughts, you subconsciously are aware of that already. You may not feel like it, but you are.
You'll be ok - I promise! It just takes time and a lot of self talk. You are stronger than you feel - I promise!!!