Ehh, thats kind of the norm for a lot of people. I like our random interactions but things always change. People drift in and out of our lives and we should just try to look back on the time we have had fun or worked together. In the end everyone always ends up going their own way at some point. Just make some time for yourself. You can still be kind but make yourself more of a priority in your life. Go for a walk, a hike? Play a game or something? Get a new hobby. In the end.. Its ok to just be doing your own thing and without others but with how our society is setup we are all conditioned to reject that. But if you want to be around others, there are a million clubs, hobbies etc... that you can get involved in.