Many fears that initially seem irrational have actually a personal precedent. For example, the fact that you become afraid when you hear footsteps when you are alone would make a lot of sense if you have a personal history of violence, of being abused or assaulted, or something similar.
If this is the case, then you may also have other symptoms of something called post traumatic stress disorder (PTSD). This is a very serious problem that can develop after a traumatic event, where the victim has sleep problems
, panic and anxiety
attacks, flashbacks to the traumatic event, and other problems. PTSD can be treated by a combination of therapy and medications, and if you think this might going on you are encouraged to talk to a psychiatrist
as soon as possible.
If you do not have a personal history along these lines, then it is possible that your fear of footsteps is just a magnification of what would otherwise be a normal healthy response designed to keep you safe. Many simple phobias begin this way (for example, everyone should have some fear of heights). Desensitization and other modalities suggested by your psychiatrist can help you come to terms with the part of this fear that is blown out of proportion.