Is OCD just being a bad worrier?

No. It is a disorder where the individual recognizes they r compelled to do things or think things that are irrational.
No. Having OCD by definition requires that one has reached a level of worrying that results in interference with accomplishing daily tasks, relationships, and other aspects of one's life.
Not necessarily. However the very first line if the diagnostic criteria is "either obsessions or compulsions", so it is not necessary to have a single compulsion to have ocd. But people generally know that the obsessions are excessive or they wonder if they are "going crazy" because they worry all the time or about even inconsequential things. If you are wondering, why not talk to a psychiatrist in your area?
OCD. Not entirely. OCD is obsessive compulsive disorder, which is comprised of obsessions (repeating unwanted thoughts) and compulsions (ritualistic behaviors to help deal with those thoughts) such as washing hands repeatedly, constantly cleaning, checking locks, and other similar behaviors. Often the emotions behind OCD are based in fear and/or anger that is unresolved and even unverbalized.