WaT's Wrong With Me?

I'm feeling so stressed up recently. What's wrong with me?
I should take things easily. Let them come and go. But i can't!!! I don't know why.
This stupid IA seems to be some kind of poison. Once taken, it will slow attack your brain then your heart. It doesn't goes straight to ur heart. It takes its own sweet time torturing you. First, making you think that it's just a 6 months during working period. Moreover, we are still undergraduates, they won't expect so much from us. Then, slowly tells you what they expect from you (giving you wee bit of stress now). After knowing that you might be a bit worry, they'll try to comfort you by ensuring you that you will be able to reach their expectation. After calming you down and leaving the job on ur own, the poison inside you will start its fatal action. It makes you worry, feel unwell, have sleepless nights and then difficuility in breathing. A slight pain will be felt at your chest area when you breath out.
Yesterday night was the first night i ever felt this kind of pain. Its possible i might be thinking too much. It's also possible that i am having some unknown illiness and it's possible that i might just be too stress. For any reason, the slow and subtle pain makes me feeling like i might die in my sleep. Like the doctor who died in his sleep at the age of 30 or 40 plus and my brother's colleague who died in his sleep at 30 plus. Life's so unpredictable, it scares me sometimes.
To have the thought of dying, all things undone will come flooding your mind. I want to..I want to...I still want to live on..continue my life ..fulfil my dreams.
I think i will never come to a conclusion on the dying thought that i had yesterday. I guess the best thing i can do is to cherish everyday and everyone that i love.