Lonely and sad but I come off as happy??

What if I am suicidal and know one knows it. I have been realizing, slowly, that I am quite suicidal. It is the alternative to everything that I do, everything that is me. If I worry about financial issues I want to commit suicide. I am so close. I have the access to medication and household chemicals that could allow me to pass away. I am sad inside and the outside one can only see happiness. The last time I let myself feel this way for too long I fell apart and had to be hospitalized. 
 
Right now I am alone. I have my parents and my brother, but I really don't have anyone else to go to. I have thought of some of my classmates as friends, but I cant even get them to do things with me that are outside of class. I am just sad inside and I don't know how to express it to others. I have not seen my psychologist since I started my Spring semester and I need to talk to her to get some advice and allow myself to relax. I need to see a doctor, I am throwing up at least three times a week and I am nauseous for the rest of the week. There are so many other side effects from the drugs that I am taking. I am discouraged about this. What happens when I am not able to be under my father's insurance and I am on my own with doctor's appointments and prescription drugs. 
 
It seem like everyday is a new challenge. Not something totally horrible, but something to be afraid of, it is something that pokes at me all the time. 
 
Goodnight Moon