I don’t think it’s ever manipulative to tell your therapist you’re feeling suicidal. In my opinion, manipulation would be saying something like “I’m suicidal, and if you don’t do x I’m going to do y”—so making your behaviors/choices dependent on theirs. Simply sharing how you feel is not wrong and is nothing to feel guilty for. That is what therapists are there for. I’m sorry you’re feeling so low at the moment.