To me, the jar breaking doesn't seem like the way you interpreted, but rather a way of the universe sort of..."undoing" your spell. Attraction spells can be very powerful magic, and when it's used in a situation when it may not be meant for the person to come back to you, then there could be negative consequences. I think that when you acknowledged you did something negative, the universe responded by the shattering of the jar to break the spell.
In other words, signs of the spell working wouldn't include the breaking of a container that you manifested your energy in.
As many people will tell you, though, any omens or signs are largely up to the interpretation of the caster. So, whatever you felt may be what it is. It's just seems to me a sign that wouldn't normally indicate success.