I have read Harry Potter series, the Chronicles of Narnia, Twilight( but i didn't like it), Percy Jackson and the Olympians and Heroes of the Olympus. What should i read now?

The Hunger Games :)

These are all selections from my own collection. I encourage you to build on this list. Try works by other authors or other works by these authors.

Inheritance cycle
Dragonriders of Pern books
Lord of the Rings
Kane Chronicles
The Princess Bride

A FEW NOTES
The Princess Bride is a satirical romance/fairy tale. Perfect for Twlight haters. Inheritance is good for those that liked Harry Potter, as they have similar themes. Lord of the Rings matches well with Narnia. The Kane Chronicles is written by the same author as Percy Jackson. Since you like fantasy, I suggest the Dragonriders of Pern as a good transition into sci-fi.

I recommend you to read Darren Shan's - Cirque Du Freak series. It's about vampires, but it's totally not like Twilight. The books are not about love , but it is a pretty addictive book series indeed. There are 12 books in the series.

If you like fantasy I remember a wonderful series I read when I was younger.
It's called The Lost Years of Merlin and has 6 books. It's about Merlin the wizard when he was a young man and his journey to becoming the legendary wizard we hear about in many stories.
You might be too old for it though. I read it in seventh and eighth grade.
Anyway, look it up to check it out! It's one of my childhood favorites!

I'd recommend the Warriors series and the Haruhi Suzumiya series.

Warriors is about a bunch of cats in the wild who are divided into clans. It has adventure, romance, action, mystery, suspense, and the classic diamond-in-the-rough character, as Rusty the house cat rises to become a warrior.

The Haruhi Suzumiya series is full of romance, humor, fantasy, action, and magic. It follows the adventures of a high school misfit named Kyon as he encounters the eccentric beauty, Haruhi Suzumiya. He finds himself stuck in her club, The SOS Brigade, as they attempt to hunt down supernatural things. Haruhi, however, is unaware of the fact that she has the power to recreate the world if she becomes bored. It becomes Kyon's responsibility to keep Haruhi entertained to prevent the end of the world.

House Of Night
BEST SERIES EVER
And the Inheiritance Cycle

How about The Vampire Diaries by L.J.Smith? I love them!

I recommend the Shiver series. (Shiver, Linger, and Forever.)

These are many of my favorites, too! I recommend Lord of the Rings, the Inheritance Cycle, Artemis Fowl, The Hunger Games, The Kane Chronicles, and The Bartimaeus Trilogy.
Hope this helps!

series: hunger games, maximum ride
nonseriesbooks: the girl who could fly

Chronicles Of The Necromancer by Gail Z. Martin (start with The Summoner) - it's set in medieval times and there's a Prince on the run for being falsely accused of murdering his parents by his brother and he can talk to spirits as well - I loved it! :)

I'm exactly like you. I love Harry Potter, Narnia, Percy Jackson and Heroes Of Olympus, but I don't really like Twilight.
Here's a few of my other favourites:

Gone By Michael Grant. Gone is a six book series, two of which are yet to be released. It's a sci-fi book series, and rather gory at times, but I think you'll love it.

The Kane Chronicles by Rick Riordan. If you love Percy, Annabeth, Grover, Thalia, Zoe, Nico, Jason, Piper, Leo, Frank and Hazel, these are the books for you!

The Hunger Games by Suzanne Collins. Amazing books. Wonderful plot and a beautiful style of writing with lovable charecters.

Cirque Du Freak by Darren Shan. They're vampire books, but nothing like Twilight, I promise.

The Wardstone Chronicles by Joseph Delaney. Dark and haunting; they're amazing fantasy books.

Artemis Fowl by Eoin Colfer. You'll warm to Colfer's style. It's funny and warming and describes a great plot.

The Maze Runner by James Dash er. Extreamly dark, and rather hard to get into, but once you do, you will regret nothing!