I Don't Like Eating In Front Of People

If I am like out and about with my mum or friend and people are walking past and things I will eat in front of others but if I am at a course work or things like that we people gathered around me I won't eat and don't like eating for 2 main reasons with eating and my nervs I sometimes end up going to toilet and i have a lazy jaw and sometimes I smack my lips when I am eating or loud at eating I don't really want people hearing that I know it can be anoing .