Just won 2 giveaways today but sadly the other one i think is fake .

contact support

Try to contact with them. If he dont want to talk with u in 7 days, report and "not received".

life is brutal :/

It's entirely possible he just didn't recognize you as the person who won the giveaway. Plenty of people will reject friend invites from people they don't know. Just wait and keep an eye on your e-mail account in case he sends it that way.

it ended less than an hour ago... maybe give him a little time? Not everyone sits and stares at the screen to send the game the second the giveaway ends

Looks like you have been... Fvcked!

You shouldn't add him in the first place, unless he's asking the winner to. Otherwise it's just pushy and an overall jerk thing to do.
It can easily come across as "I won, gib me mai gaim!"