I have. Sadly, there's not much we can do. Depending on how old are people, they are susceptible to changes in a matter of few months, especially teens or people on their early 20s, because they are still getting to know themselves and building their adult character traits. Also, there are fake people who just seems like they care and then they don't anymore depending on what's convenient for them at the moment. The important thing is that you know the real ones and stick to them.Also, maybe you'd like to evaluate if that's something that you have been over analysing due to insecurity?