Most Helpful Guy
I think it's because he didn't really want to call you. If he did, he'd have found a way to make time. You shouldn't take that personally though. It doesn't mean there's anything wrong with you, just that for whatever reason (which might have nothing to do with you) he's not interested right now.
I think the real question here is why you "never feel good enough for any guy" because I'm sure you have positive qualities that the right guy would find very appealing. Why do you not feel good enough? My guess is that you're being too negative about yourself. Look for the positive things and be proud of those. We all have some negative things (either physical or personality). No one is perfect. It's always good to try to work on the negative personality traits (there's usually not much you can do about physical ones) but it's important to see the positive things in yourself and be proud of them.