I've spent many months out of a year obsessing over suicide since I was very little (around 8 years old). I remember it wasn't 'til around fifteen that I realized thinking like that wasn't 'normal'. SI in itself, while extremely unpleasant, isn't entirely a cause for extreme concern about crisis. It can (and in my case often has) turn into full-blown planning and intentions. I suggest, even if you feel embarrassed (though you shouldn't), that you be honest with your T and work through these thoughts now before it can exceed what classifies as ideation.