Stress

HELP ME!!! I don't know what happen to me nowadays. I become more and more forgetful. huh.. Ok, is about my friends birthday, I know what date and what day. And i am planing what to buy, what to wish him/her. On that day itself, i forget everything, i even once also didn't think about that day is my friend's birthday. OMG! Not once, is already twice. Nono, is third time the same thing happen! Then i told my friend why i forget this and that. Most of them give me the answer is "you are too stress". huh? I really didn't think about i got stress. Because i really enjoy my life, studying also enjoy. When i heard that i am too stress, i was shock and i ask what the feeling of stress. Scare i continue forget thing, important thing i forget. I really can't imagine that i forget again and again. It was like, a new thing happen in my life, and didn't happen before. Blank. Totally blank. Confuse the feeling. Afraid yet scare.

Is it that i so forgetful is a stress symptom?
What is the feeling of stressing?
How should i overcome it?
Can you all help me?
PLEASE HELP ME.