Help, I made a mistake.

So, basically I had went ahead and had my coworker cash me out whilst I was off the clock. I had purchased 20 dollars worth of stuff, just some medication and a drink for home. I told them to suspend the transaction and sell me a giftcard so I could get my employee discount, as I had done this for one of my TLs a few months ago and didn't think much of it. She seemed super sketched out so I called in once I got home and asked to talk to the current closing TL, and she told me she's 95% sure it's against store policy and that she needs to talk to HR. I have no writeups but I'm super worried I'm going to get fired over an honest mistake. Any suggestions/input? Thanks.

UPDATE: I got fired for a completely unrelated reason, supposedly due to harassment and racially profiling guests. they refused to elaborate further and then kicked me out in the rain while I was waiting for a ride. Thank you target, I really appreciate it. I did nothing but earn for this company just to get kicked to the curb.