Giveaway created three times

You probably clicked the button "create giveaway" 3 times because it wasn't loading, this leaded to 3 giveaways, if you delete them all you will lose slots, if you delete just 2 you won't lose all slots to create new giveaways, and any successfully confirmed and received giveaway gives you extra slots. If you delete 2 now, be sure not to delete more in future, because you may lose your slots to make new giveaways, and to ask for more you have to write to support. And remember if page is not loading and you click multiple times, it's only for worse.

Delete 2 of them and then contact steamgifts support and tell them what happened. They should give you back the 2 slots for giveaways, but it could take a while. Low number of support people plus lots of people sending in tickets plus it being the holidays means don't expect an answer anytime soon. but they might surprise you.

One time i created 11 :DD just erase them and ask the support if they can give you the slots back