Summer Vacation

I have always loved holidays .but the times flies are too fast.I only have only a few several days left. I'm so sad, I haven't even haven't started  to do my homework!

summer vacation

I have always loved holidays, but the times are they go by too fast. 

I have only several days.   "only" means very few, but "several" means many. These words mean the opposite of each other, so you can't use them together or side by side, like this.   I think you meant to say this: 

"I only have a few days."

I'm so sad, I even haven't start do my homework!  This is really close, but you switched two words around.  They are in red.  Also the verb "to start" needs to be in this form: started.

"I'm so sad.  I haven't even started to do my homework!"

Nice work!  It was really easy to understand!