You're right. Addressing the suicidal and homicidal stuff is of primary importance. I guess having had them myself I have somewhat distanced myself from them.
Accessing help can be a sensitive issue and I think it is best not to alienate the individual in the process.
Help can range from going to the ER, talking to a friend, talking to a family doctor, etc.
when ever someone is feeling homicidal its time to get serious help. no offese to above yes you very well have low thyroid it sometimes leads to depresion..I am most concerned you hate everyone in school WHY? and your statement of wanting to kill some one..have you told mom these 2 things????..your so right you need help snd it is there consider a short term behavioral center..they will put you on med and observe how the meds effects you..theres a lot of cognotive therapy. the stigma still excists w some people..now in med community its called a brain disease, your chemicals are off.
Dr Phil is not a psychiatrist. Not unless he went to med school since I last saw him.
You could try talking to your mom or a responsible trusted adult (a teacher, a family member, a priest, etc). If your mom isn't receptive then try your school counselor.
You could also start with your family doctor if you feel more comfortable with that. It's important to first rule out any medical conditions (such as thyroid problems, etc). Your symptoms could also represent low thyroid. Ask your mom. She may be more receptive to a physical versus a mental illness.
Not all psychiatrists are like that. Some can be quite helpful. Its a matter of finding the right one. What you describe could be depression. Anger and feeling alienated can often be a part of depression but only a psychiatrist could provide a conclusive diagnosis. If your mother would not be supportive of your decision to seek help speak to a guidance counselor and perhaps they could make a further referral if needed.