I feel like I caused a woman I liked to leave social media.
Do you know the reason behind her leaving? Are you certain you did something wrong?
Actually, I've heard that she left social media because of her abusive ex.
Since you stated that the woman you liked left social media because of her abusive ex, you shouldn't feel like you are the cause of her leaving. Instead of blaming yourself for not doing more, you should understand that you can't control the behavior of others and accept that you did nothing wrong.
I'm going to try to find her and apologize.
I suppose that seems like a nice thing to do but usually people do not apologize to others if they have done nothing wrong.