How can i delete my free weekend games from steamgifts account ?

You can't. If you haven't played the game yet, wait until the free weekend is over and force resync. If you have played it, you'll have to wait two weeks more.

You have to wait till Monday then re-sync your account.

I still can't enter Awesomenauts giveaways :(

Right Click on the game -> Delete local content, than resync on Steamgifts.
Woths only after the free weekend ended.

Thx the answers