I will offer you my opinion but please know that I could never accurately diagnose anyone based on a very short letter. It is always in your best interest to consult a mental health professional in person, and ask for their advice, feedback or diagnosis.
The symptoms that you wrote about do not strike me as symptoms of schizophrenia. Schizophrenia is a thought disorder marked by delusions and paranoia. For the most part, you do not seem to be experiencing these symptoms. Your symptoms fall more into the realm of schizotypal, schizoid or avoidant personality disorders. It could be any one of the three disorders, or none of these three, but it seems that you match the criteria for schizotypal personality disorder more than the latter two disorders mentioned.
Persons with schizotypal personality disorder struggle greatly with issues related to social interaction. They describe themselves as being extremely shy. For them, interacting with others can be such a painstaking process that they choose to avoid all and any contact if possible. Their fear of rejection, much like what you described, is so great that it causes rifts in friendships, work and family relationships, and so forth.
Those with schizotypal personality disorder often, unfortunately, do find themselves with few friends. Many say they prefer to be alone or are convinced that being alone is desirable. It is difficult to know if those with schizotypal personality disorder truly prefer to be alone or if they have convinced themselves of this as a way to rationalize or justify the act of not making contact with others. The idiosyncrasies of the disorder are complex.
In addition, you also seem to be displaying symptoms of depression and anxiety. This seems to be in line with what your psychiatrist thought as well. You mentioned that you are having physical symptoms in addition to your psychiatric symptoms. It would be wise to see your primary care physician to rule out any physical problem, if your psychiatrist has not done this already.
I have offered my opinion about what disorders you may be suffering from. I am compelled to reiterate that my judgment on this matter is based on scant information. You mentioned that you see a psychiatrist and that is a good beginning point. As difficult as this may be for you, given that you have difficulty interacting with others, I would suggest that see you a therapist in addition to the psychiatrist. Medications are a good start but a skilled therapist can help you learn proper social skills, thus increasing the likelihood that you will have more positive interactions with others.
I hope this helps give you insight into what may be going on. I wish you the best of luck and as always, please write again if you have further questions.