It is easy done. If you klick on the broken heart while watching the profile it is already finnished. I myself too managed accidentally and did not even notice first, because there is no questionnaire if you really want to do this. Klick and done. As far as I know there is no notification either, but I am not certain.
To get on this button while typing or whatever may happen very easy even without getting aware. Especially at a laptop where I never know what my cursor does while typing coz my thumbs or palms may touch the pad in between. 
Don't be miffed though. It may happen without intention. Restore your status and be happy together.