Messages from my icloud instead of my number.

Hi! For about one month, my contacts have recieved messages from my icloud instead of my number. I have tried to change it in "massages" in the settings app, and there are two options , my number and my icloud, (in send and recieve), but I cannot click to choose my number, only my icloud. I went to get help at a store called media markt, but they told me to ask for help from apple. I cannot facetime, and my messages only get sent from my icloud. I want to be able to facetime and text my contacts from my friends. Please help meeee