My cat is behaving very oddly

Tweet

This is the cat with the litter box problems. Now, my cats go inside and outside. She stays inside most of the time, though. She will go out for a brief period, maybe 20 minutes or so, in the morning. Maybe she will go out for another brief period in the evening. She spends the rest of the time inside. she sleeps a lot. Sometimes she sleeps in bed with us. I stay up late at night writing, and she will often hang out near my computer with me. This is her normal behavior. Well, for the last several days, she has been staying outside almost all the time. I have to make her come in. Yesterday when I made her come in, she ate. Tonight when I made her come in, she didn't even eat. She just went off to the back room of the house, all by herself, and went to sleep in a corner. Something is obviously not well with her. I think I am going to make an appointment with the vet in the morning. But does anyone have any ideas about what could be wrong with her? Kelly