To answer your question directly: Yes, it would be wise to see a professional. You are experiencing serious symptoms and have been for many years. Professional help can assist you in decreasing your symptoms and improving your life.
Your family is worried that you have schizophrenia, but that may not be the case. Though I cannot provide a diagnosis over the Internet, your symptoms seem more characteristic of dissociative identity disorder (DID) than schizophrenia. The specific symptoms that I am referring to include: memory loss, your description of feeling trapped in a body that is foreign to you, your awareness of other personalities that are dissimilar to your own, and the fact that some of your behavior seems to be outside of your control.
Other concerns about your situation include your tendency to be isolative, your history of suicide attempts and the fact that you spend 70 percent of your time contemplating suicide. All the aforementioned concerns significantly increase your risk for suicide. Under no circumstances is suicide the correct choice. In addition your family, who obviously loves and cares about you, would be devastated if something were to happen to you. For those reasons, it is imperative that you do what your family is suggesting and meet a mental health professional.
For many people, the thought of getting help is frightening. That comes from not knowing what to expect. Fear is understandable; however, please know that you have nothing to be frightened of. Mental health professionals are trained to assist their clients in solving their problems. They sincerely want to help you. Their ultimate goal is to improve the quality of your life.
Listen to your family. They are doing the right thing. You are blessed to have such a caring and loving family. I hope that you will attend the appointment and get the help that you deserve. I wish you well. Please take care.