Mine had similar behavior at same age. Stopped eating and laid around all day, over time lost some weight but not a lot. Good to rule out everything though, would really advise getting fecal check. Mine had a mild case of pinworms and nasty bout of coccidia. After round of meds she stopped eating completely for 3-4 mos. I gave her baths every other day and fed her babyfood. Never turned the lights out cause she never fully went to sleep, just super lazy wont move all day kind of stuff. In late November she snapped out of it and turned into hormonal hanna for 3 mos, eating like a pig, gaining all her weight back and then some. She was crazy all day, scratching and pacing in her tank. I had to let her out 2-3 times a day so she could run all over the house and get it out of her system. Only in the last 2 weeks or so has she gone back to her lazy self, snoozing and sitting in the same spot all day.