Breaking up is complex and, usually, it's a difficult decision. The two of you may have been close -- or even best friends -- so for her, the thought of losing the friend she has in you may be disorientating. On her way home she could have driven past the restaurant where you had your first date, and it could have triggered a memory. If she isn’t over you, calling may be her way of keeping tabs on you to see how quickly you have moved on. She may be looking for some kind of confirmation that she has to let you go.

Perhaps she is hoping to reconcile. You may be too, if you are answering her calls. If so, step back and assess the quality of your previous relationship with her. Think about important things that may have ended your relationship like too much possessiveness, dissimilar interests and lack of support, which are the top three reasons for breakups, says Leslie Baxter in the 1984 classic study in the "Journal of Personal and Social Relationships." If any of these factors caused the breakup, they may continue to be problems if you reunite. In fact, once you break up the first time, then you are more likely to continue to break up and reunite, reports a 2013 study by Amber Vennum et al. in the same journal.

Another reason she could be calling is that she wants to be friends. If, however, it is very soon after the breakup it is possible that she has not dealt with the emotions surrounding your parting. Being friends may be a good way of avoiding that grief. For example, if she calls you to share frustrations about her work day or begins talking to you as though nothing happened, she may be using you as an emotional crutch. If you are not interested in this kind of relationship with her, keep the conversations short and stop answering her calls.

A breakup can be difficult to accept, even when it was mutually agreed upon. She may feel there are conversations that still need to be had for her to be able to move on. Getting through a relationship change such as a breakup can be difficult for some partners and communicating afterwards can lead to closure. This could allow her to move on, suggests Rene Dailey et al., in a 2012 article in “Communication Quarterly.” Answering her questions is a kind gesture and may provide her with the closure she needs.