Coming to this a little late, but...
A number of computer security firms have looked at this and have proved that Facebook, etc. do not listen to your conversations. Stories don't go away and are sometimes fuelled by the press, but the reality is that controlled experiments have proved that they are not lying. They really don't listen to your conversations. If they did, your phones would be using a lot more data than they actually do.
The reality is a mixture of cognitive bias and sophisticated algorithms.
To take cognitive bias first, we see ads all the time. Most of the time they aren't relevant to us so we just scroll past them without taking them in. So, in OPs case, she may have been seeing ads for Luxury Escapes regularly for some time but simply ignored them. Then she had a conversation with her friend about Luxury Escapes. The next time an advert for Luxury Escapes pops up, OP would notice it because of the conversation with her friend. So, if it is cognitive bias, it is not the case that Facebook has suddenly started showing her ads for Luxury Escapes. What has actually happened is that OP has suddenly noticed that Facebook is showing her ads for Luxury Escapes.
The other part of it, the sophisticated algorithms, builds on the data Facebook and other social media collect on you. To take Facebook, they know who your friends are and what they are interested in, so can infer that you might be interested in the same things. They know where you are as long as you've got your phone with you or are sat at a computer where you are logged in to Facebook. It knows who you are spending time with. It can track you across all your devices. It can get data about your calls and texts (although it can't access the content unless you use Facebook Messenger, which is why Messenger encourages you to use it for all your text messages). All this data can be used to figure out what you might be interested in and serve appropriate ads.
Of course, Facebook's algorithms aren't perfect. If, instead of simply scrolling past them, you pay attention to all the ads, you will see how often Facebook serves up ads that are completely irrelevant to you and your interests. And, if you do it for a while and keep notes, you will see how often that advert has been served up to you before you suddenly notice it because you've talked about the subject with your friends.
So no, they aren't listening to your conversations. They have much better ways of figuring out what ads might be relevant to you.