it does sound as if it could be OCD. a friend of mine was troubled with similiar patterns. she was given a med by her doctor and it helped her.

i have a thing about finding my house keys hours before i need them.....and i really get freaked about it......as for as the phobia of abnormally large things, i don't know. i googled it but didn't find anything.....you might try WebMd....good luck.