<human>: I just said no to a family member when they asked me for a favor.  I never say no to anyone.  I get knots in my stomach and feel mortified at even thinking it.  It is SO hard to say no.  I don't know what causes this, or what makes it such an obstacle for me.  But today, I said no.  They asked me to watch their dogs for a week.  They only ever contact me when they need something and I got sick of it and very nicely said no.  Normally Id do anything for them but this time I felt like I had to say no, and my current circumstances woulnt allow me to do what they asked.  Now they stopped replying to my texts (this was a text message conversation) and I am freaking out.

Can you condense the text into a few key points?
<bot>: I hate saying no and am terrible at it.  It makes me feel like a selfish and shitty person.  Does anyone else struggle with this?  Anyone have advice for how to overcome this anxiety saying no causes?