haaa.....I'm very tired..

Yesterday was my birthday. However, I was very confused....I didn't know why I was confused/like this..I couldn't focus on my studies, and play with my friend....I don't know what I waste all the day which is significant for me on doing.

I'm not sure what you want to say with your last sentence. Do you mean: "I don't know why I wasted all the day which is supposed to be significant for me." ?