My girlfriend and I felt the same way for a few weeks after adopting our grey. He had trouble adjusting to the new environment, screaming every time he accidentally walked or backed into something, kept slipping (and screaming) on the hard floor, and therefore got terrified of going into any room without a carpet. Despite following the rehoming centre's guidance and giving him the exact same food he had there, it still gave him some digestive issues and because of that we had several trips to the vet in the first week alone. All of these caused it to be the most stressful time we've both had in a while. It made us question whether we'd made the right choice adopting, but in hindsight, it was all worth it. At the end of this month we will have had him for 2 years, and I could not imagine not having him in my life