Awkward work situation makin me anxious. plse help.?

What would u do if u felt a work colleague got the wrong impression of you, but when u tried askin them (via facebook) if u could talk with them, they unfriended u before u even had chance 2 say wot u was going 2 say to them. & also knowing that you could not speak to them in work (hence message via facebook). Now he thinks I fancy him & I don;t. What would u do?