How can i get used to sparring in the ring?

iv started training in a thai boxing gym but i am scared of sparring i dont know y i tend 2 get really nervous and feel useless, i havent sparred yet but thats the felling i get wen i have 2! im scared 2 get hit in the face ...! plz and i mean plz how can i get used 2 this! plz answer !!!!