My stupid mistake

I wrote awhile ago about this sweet little kittie who has been hanging out at our place, sleeping on the porch to keep out of the cold and we feed it.  When I go out in back, I always walk out first and check all around to make sure the cat isn't there because our inside cat hates other cats and goes after them.  I walked out, looked around and didn't see her.  I let our cat out (we have the back area fence in so our cat can't get out), well evidently the cat was around the corner inside the fence.  Our cat puffed up and stood still.  I knew instantly what was up and when I walked down the stairs I saw the cat in the cornered.  My cat didn't actually fight up close but screached and howled and hissed and ran up like it was going to attack.  Then looked at me and I yelled at it to get in the house, but the poor little kittie was so petrified and scrambling to climb the fence to get away.  I felt so awful you can't imagine.  It took so long to get the poor thing close enough that we can stand outside and it won't run.  A little while ago it was laying on our front lawn falling asleep.  It's getting cold out now and I hope she comes back to the porch again to sleep out of the cold.  Just can't believe I didn't go all the way down and check around by the greenhouse.  Stupid, stupid me.  Okay, just had to tell someone cos I'm heartbroken that the kittie is so scared.  Well see tomorrow when we get up if she's come back.