Hello.
It will be erroneous to say antidepressants may have caused her to take the decision. What looks more probable is that she wants time and space to sort things out for her. She may be on a path to recovery from her depression. And often new insights start coming up. She may not be in a position to explain to you all that is going on in her head. However, you need to pay due respect to her decision and avoid searching for the cause of her decision.
There are more chances she might be telling you the truth that it's not you. This also gives a hint she needs space for herself. I hope you are able to cope up with the break up successfully. You can always present yourself to help her when it's needed.
Take care.
Abhijeet Deshmukh, MD
(This post is for the purpose of providing medical information and is not a substitute for a face-to-face consultation with a doctor. This post is not intended to give or rule out a diagnosis, create a doctor-patient relationship or replace an existing one. I am not able to diagnose medical conditions online. Please consult with your doctor or a qualified healthcare provider for diagnosis and treatment options)