Not to worry; you didn't send it to anyone. All you did was create a link to the file that you could then send to whomever you wanted to.
If you're worried about that link falling into the wrong hands, you can simply go to your Sent Files view, select the file by checking the box to the left of the filename, and then clicking Unshare:
That will render the link that you created unusable.
Hope this helps.
Thank you so much I was really stressing!
Apologies for the stress! I forwarded your comment to our designers; perhaps they can come up with a better way of conveying this information.