Letting go of people
Sometimes you just outgrow people, and yes it can sometimes become very lonely but some connections are just not meant to last. Though letting go of people who may have had an effect on who you are is going to be somewhat difficult depending on the person, it will be for the better. That being said at the end of the day you can either choose to stop growing and constantly look to the past or you can accept the fact that people grow apart and move on. Growing will present you with a whole new perspective and you will eventually find that people who will be willing to share the view with you will begin to gather alongside you.
Changes in life are inevitable, and these changes usually carry a kind of positive/negative effect. There are times when the changes are really really good and other times when they are just down right horrible, but change is a part of life and its absolutely necessary for progress, it's also possible that the good/bad changes will make you stronger. Fighting the bad and ignoring the good will just leave you feeling empty and nobody wants that feeling. The ability to cope with the bad times and to recognize enjoy the good times are the only way to be somewhat happy.