20 Most Recent Omega Constellation Double Eagle Gold & Steel 1211.30 Watch for Men Questions & Answers

A mechanical watch will tend to stop in the same place if an internal gear is slightly unbalanced and/or there's a spot of grease/dirt that makes that particular point on a gear slightly more difficult to pass. I've often seen watches with day/date indicators stop just around midnight, as it takes more energy to advance those dials than just move the hour and minute hands.
Try winding your watch with the crown as opposed to shaking it to wind it via the automatic rotor. Actual winding will bring your mainspring up to full power much faster than a whole lot of winding via automatic rotor. See if this changes the behavior of the watch. If it doesn't, you probably need to have a watchmaker take a look at the watch. He or she will probably recommend cleaning the movement to clear any dirt that might be causing the problem.

just behind the dial or on the box.

different watches have different case backs. You need to send a picture with yours or send the model number so we can see what is the case back system. Omega has many vintage ladies models.

Did you get water on it? Does it need a new battery?

Please contact a local jeweler for this type of repair. Fixya does not sell parts or have anyway to look them up for any product, sorry.