<human>: Can you succinctly summarize the text in 1-3 sentences?

I'm the youngest (by a big margin) in my family.  I have always been very close with my mom.  In the last few months I have started to feel like I can't agree with her on anything. She can be very negative and is always telling me and my siblings how to live our lives.  I live in a different state and now it's like talking with her is a chore.  I know her heart is in the right place but every time she comes to visit I snap at her constantly and act as if every question she has is stupid.  I know that this is unfair but I feel like no matter how much I tell myself I will be nice I can't manage it when I'm around her or talking to her.  It's gotten so bad that last time she was her she said she won't come around anymore and feels unwelcome.  

A few important details, she has a mild form of muscular dystrophy (as do I) it's quite mild while young but gets worse with age.  A doctor told her that if she did not stop working (as a mail Carrier) it would shorten her life, she continued to 
Work for another year, I was furious when I found out.  She seems to have complete disregard for her health sometimes but then proceeds to tell me EVERYTHING That I'm doing wrong Heath wise.  I feel really bad since she has always been my biggest supporter and I know she just wants to look out for me.  I don't know what sparked this temper problem I have but I fear that I'm going to hurt our relationship for good if I don't get it under control.
<bot>: I feel like I cannot be nice to my mom, I'm always short with her even when she has good intentions.