you don't say how old you are and how old your mom is...but you did mention being an only child..sometimes parents are more fearful if we only have one.
and I could not help but notice in reading your postings that you chastise your mother for being one way, but I see a lot of similarities in your behavior from what you have written.
not everyone is OCD or crazy because you catch them on a bad day...not everyone is "unhealthy", it is how you perceive them. most folks are just normal, working through a bad economy, dealing with the death of a parent or spouse (as your mother and grandfather are, you might want to cut her some slack, she is a caregiver for her parent, how would YOU deal with it?) and getting through a work day.