I'm not sure which name you know it by- I was taught it's a grafted cactus but I remember people here calling it a moon cactus. Either way, it's dying. It's one of the two plants I bought to have some bright color at school and I took it home over winter break so it could be cared for. It wasn't watered frequently as I'm not home often but as it's a cactus I figured it would be enough. Yesterday I retrieved it from my house to bring it back to school and the thing was wobbling all over the place. I know that means no roots. I dug it up gently and found that it has a very small/weak root system. The plant itself doesn't seem to be suffering... yet. So I was wondering if there was a way to fix the problem? I dug it back into the soil and gave it a bit of water but I'm not sure what to do?

Ive loved houseplants ever since I was a kid, my grandmother taught me. Majored in Floriculture in High School.