Giveaway and rules question.

Check your email to see if it was sent there. After 7 days you can mark it as not received. The creator can reply to your comment if they want to sort it out.

Try to contact them on this site and through steam if possible. Some creators only come onto the site like once a week and may just have forgotten about it. After 7 days if no response, as combatbeard has said you can mark it as not received if you wish. Best of luck and I hope it works out ok Xarellah.

Don't forget to check the spam/junk folder in your email. A lot of emails that I have sent with gift links and also emails sent directly from Humble Bundle as gifts are constantly going to people's junk.

Check the description of the giveaway.
Some people might need you to add them on steam so they can send you the win.
Or like others have said, maybe the email you use with steamgifts has it. Sometimes people send it there.

I'd suggest reading the FAQ, specifically the section titled "If I win a game, when can I expect to receive it?" where it explains the creator has 7 days to provide the gift and to not contact them during this time. By contacting them early they may simply wait the 7 days before providing the game out of annoyance. As it is stated in the FAQ to not contact them, you may be in violation of the rules. If that is so, they may be reporting you and asking for a reroll, though I don't know if that offense is great enough, but it is possible they may be doing that. It also goes on to explain what to do in the event that you do not receive the game.

Thanks everybody for your help!