To keep track of the items you are or were bidding for, you can use the list shown under the tab "Bids" on the auctions page.

The page is split into two parts:

• Your currently running auctions are shown in the list at the top of the page. First and foremost, here you can see whether you are still the highest bidder for the item you want to buy. Additionally, you can change your currrent bid. 
• Below the list of your currently running auctions, you will find a list containing all of your previously finished  auctions. Here you can see whether you won or lost the auction for the items you bid on; additionally, you can see the final price these items went for. 
  You can delete finished auctions from the list by checking the box in front of the respective auctions and clicking the "delete" button afterwards.