It could be a number of things; but overall, the most important thing to do is see a physician and counselor. The physician can rule out medical causes of not being able to eat solid foods, while the counselor can seek out psychological/emotional reasons for not being able to eat, as well as not being able to eat in front of others. Please see both, even if you don't think that you have body image issues, or emotional issues (some anorexics/bulimics become disordered purely from a sense built up self-hatred and feelings of not be deserving of basic things, as a form of self-punishment). Following from this, it could be an issue of control, which uses food/body as an outlet (see The Secret Language of Eating Disorders).

Just a few other things that could be causing your symptoms: physical ailments/diseases (another members ED was caused this way); or Social Phobia/Anxiety Disorder (causes inability to eat in front of others). An any case, it is CRUCIAL that you seek medical/psych help, as your current habits will quickly deteriorate your health.

Best Wishes,
Jessie