I've never had a lot of friends in my life, but have had a couple 'best friends' who I was very close to at different points in time.
One of those 'best friends" essentially told me she wanted nothing to do with me anymore a few years ago and she never actually explained why, but I strongly suspect it's because I've been dealing with so many physical and mental health issues and I was just a drain to her.
The other best friend and I drifted apart and reconnected about 5 years ago via Facebook. We have never become as close as we were long ago but I understand that and didn't expect it, but we did become close enough and also based on how very, very close we were years ago that I opened up a bit and told him about my mental health issues and struggling with suicidal thoughts. He didnt say much at that time though did act sympathetic...and then he's never mentioned it again. I have never brought it up again and never will.
The only other person I've confided in about being suicidal is MY OWN SISTER who has never brought it up again either but then, she and I have never had a great relationship and I only told her what I did one night when I was feeling especially emotional and she and I were going through a (very short) period of time where I (mistakenly) thought she and I were getting closer. I regret telling her what I did now just because it hurts to realize how little it, and I, mean/t to her.
I agree with Mr2005 in that most people only 'care' about you to the point where you can offer THEM something -- attention, a good time, material things, whatever it may be -- but once they can't get that from you anymore, or you're unable to provide it or they don't need whatever it is anymore...they stop 'caring'. Of course there are some truly sincere people and genuine friendships out there but it seems like to me that that's the exception, and those people are incredibly fortunate. I've never been that fortunate to have a genuine, long-lasting friend that TRULY CARES, though, so maybe I'm just bitter and looking at the world through a skewed lens.