I know I'm late to respond, and hopefully you already sought help, but please remember if you made a plan with your therapist it means she/he WANTS you to use it when it is needed, which sounds like in this case it is. You seem like you're in a panic moment, you cannot think as clearly when you have all those thoughts that seem overwhelming. You made the plan for a reason, right? Because of times like this. Try to think of your past/future self - if your past self wanted a suicide plan it's because you wanted to know you have help during the tough times, and your future self might want to as well. You have options, please, please utilize them and let someone help you.