Hi,

I am very sorry to hear what you are going through. Can you think of any reason why you feel like you are abandoning your parents? Also, what kind of thoughts go through your mind when you have trouble sleeping? I know you say you feel anxious and afraid, but what exactly is it that you feel anxious about?
Could you tell me if you are living alone?Do you have any roommates or a significant other? I feel like you should speak openly to your dad or at least close friends about the feelings you are having. Do you think your parents would support and understand your dilemma?
Often, we are blind to certain causes and triggers that make us react the way we do. I know you feel like your sister's death has nothing to do with your feelings but I'd like to ask you to reevaluate this idea. What were the circumstances of her death, how did you cope emotionally and how did your parents cope?
I just want to say that its wonderful that you reached out for advice. It is not easy to recognize that you might have some issues and this is a brave step forward.
In the meanwhile, keep analyzing your thoughts. Whenever you are disturbed try to take notice of the kinds of thoughts you're having and try to pin point why you must be having them. Write them down and read through them when you feel calm and collected.

Also, feel free to write to me anytime you want to talk or share. I will be happy to lend a ear!
Take care