how do you know if you have Schizophrenia?!

People with Schizophrenia will show characteristics of auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social or occupational dysfunction.

They will have hallucinations: mostly hearing voices, and often bizarre or persecutory in nature, and disorganized thinking and speech. The latter may range from loss of train of thought, to sentences only loosely connected in meaning, to incoherence known as word salad in severe cases.

Also, social withdrawal, sloppiness of dress and hygiene, and loss of motivation and judgement are all common in schizophrenia. There is often an observable pattern of emotional difficulty, for example lack of responsiveness. Damages in social cognition is associated with schizophrenia, as are symptoms of paranoia (mental disorder of being overly paranoid, with hallucinations),,and social isolation commonly occurs.

You said that you might be Schizophrenic because you often think about suicide, but this is less likely to be Schizophrenia, because Schizphrenia does not directly lead a person to be suicidal. You might instead consider Depression, post-traumatic stress disorder, etc. Check up on the internet of suicidal symptoms, etc.
Also, I would suggest you to seek counseling if you feel this way.

Suicide and Schizophrenia:

yes it's true that a patient could be suicidal, thinking about suicide, etc. Although, this is just a prognosis. A patient does not always get suicidal symptoms by having this disorder.

"There is a higher than average suicide rate associated with schizophrenia. Attempt to suicide can be a part of what would happen as the prognosis of the person with this disorder. There are a variety of risk factors, including male gender, depression, and a high intelligence quotient.
Schizophrenia and smoking have shown a strong association in studies world-wide. Use of cigarettes is especially high in individuals diagnosed with schizophrenia, with estimates ranging from 80% to 90% being regular smokers, as compared to 20% of the general population.Those who smoke tend to smoke heavily, and additionally smoke cigarettes with high nicotine content."

Schinzophrenics hear things, see things, or can suffer from dellusions, extreme paranoia and such. Although some can be suicidal, being suicidal does not make you schizophrenic. You may have a mood disorder, but a doctor would have to diagnose you. Schizophrenia is hard to diagnose while a mood disorder is not. Schizophrenia also rarely occurs at a young age and usually starts to occur at around 20

Diagnosed with a mood disorder but may be having early stages of schizophrenia (all said by a doctor!)

Ugh.. No, it doesn't sound like you have schizophrenia (maybe some mental retardation). Schizophrenics have visual hallucinations and paranoia and all sorts of other delusions. Thinking about suicide is completely normal, unless you are actually planning on following through with these thoughts.

you definitely don't if you only have thoughts of suicide! cheer up mate, brush ya shoulders off. if ya cant see wipe your eyes n look straight forward.