Happy?Joy?

What is definition of happy and joy?An item that u enjoyed at the particular moment and it stayed only in your short term memory is known as happy,joy is an item that u are happy with and it will stay in your memory.This is definition by Mimi when we on the way back from uni one day.
For me,it seemed that i never been happy from my heart since very long time ago,may be after secondary school???I don't know how to describe.I don't know anybody else understand what i mean or not.But,i think this is the problem with human growing,when the more things we see,the more so called thinking and hesitation we need to deal with.
Sometimes i felt grateful,sometimes i felt tired,exhausted to deal with things like that.Relationship among people.Do i mind what people think about me?I used to very "concerned" about what people think bout me.But now,i think no more.May be towards the person whom i really closed to,i don't want them to be sad,i don't want my said wrong things make them sad,i don't want my over sensitive make their life hard.I mind what they think about me,because i want them to be happy.
Studying medicine?Why?What's that for?No idea,but one thing for sure,i am interested to know about human.that's why i am here.Everytime when i found something new and interesting,i would be so excited.Luckily i still have the learning will.
A new day,a month to state exam.No more asking how,action is more important.