Wow it sounds as though you have a lot of things going on in your life. You're right it is so difficult to see your Grandma getting older and having to put in a retirement home. Just make sure you keep writing to her so you can still feel close to her. This may cut down on missing her so much.
Sounds like your spring break visit with your brother and sister-in-law didn't go as well as it could have. Maybe it was because you had so many other things on your mind. Are you able to talk with either of them (your brother or sister-in-law) about how you are feeling about things? It's possible that they would understand what you are going through and be able to provide with some support.
It appears that you have a good relationship with your school counselor and that's great! Make an appointment to see him as soon as you get back to school. I
n the meantime keep a journal or write about how you are feeling in order to prevent bottling all your those thoughts up. And know that you can call our hotline at anytime we are here 24/7.
Take care.
Nikki