Joint compound for texturing.
I was told I could use joint compound for a texture over a sanded down texture which I did and it looks okay. I put it over a sanded surface washed with TSP and sanded. There was no other prep. Have I gotten myself into a mess by taking this advice? Also can I now put a semi gloss over it?
It should be OK. Priming before the texture is a good idea. You would have already noticed problems if there was going to be any.
All you need to do now is prime the texture with a good latex/acrylic primer then paint with your favorite sheen, semi-gloss will be fine.