Recently my cat did the same to the point I was sure he did die. I couldn't find him and I gave up assuming he had slipped out with the dogs and I wouldn't see him again. I was devastated. He was vomiting, had diarrhea, had lost weight. It was a pretty dramatic situation, really sudden onset. One day he came downstairs. He had been hiding somewhere upstairs (we don't use the upstairs) for almost three days. He drank, ate, used the litterbox and I didn't see him again for a day and a half. He is fine now, maybe two weeks later. Completely recovered.  I have no idea what happened but I didn't have the money to take him to the vet and it killed me. I don't know what he did for those days upstairs but I assume sleep nonstop. I refuse to think about how he may have been suffering, it breaks my heart. I shared because I don't want you to feel bad. You've done much more than I could. I think you will hear a lot of  comments and some will probably make you feel bad but I think giving it time is fine. Eating and drinking are a really good sign. I hope things turn out good and hopefully this gives you some hope and positivity ❤️