Dear Harsha,
It sounds like you have been suffering a long time and I commend you in seeking help. It sounds like your symptoms have seriously negatively impacted your ability to function optimally.
Briefly, here is the emotion cycle: how you think, leads to how you feel, which leads to how you act, or think>feel>do. In order to feel better, feel less angry, sad, irritable, etc., you can change the way you think, or change your behavior--what you do. Changing the way you think would be like being grateful for what is going right in your life, thinking positive thoughts, focusing on the things you do right. Like you can tell yourself: "I do things well. I am a good person. I have a lot of patience. This isn't really that big a deal, so I don't have to get so angry." Even if you don't believe these things, you can train your mind to think this way, which will help you to feel less angry or irritable or bad about yourself.
The other way of intervening is through changing your behavior, like taking a time out before responding, exercising, eating healthy, sleeping enough, being good to yourself, so that you can feel better. Doing very slow deep breathing will also help relax you, lower your blood pressure, and decrease your
anxiety and anger--breathing very slowly in, hold your breath for two seconds, then breath very slowly out, for at least five minutes three times a day. You may need to build up to that much.
I strongly recommend that you obtain a full medical exam to rule out any physical problem that may be impacting your symptoms. If you have no medical issues, then I strongly recommend that you further seek treatment with a
psychologist or other therapist to address your anger, irritability, low self-esteem, and suicidal thoughts. This person can also recommend whether or not you would be a good candidate for medications. Good luck to you.