Missing the Reality

Last Friday, I found out that two close friends of mine are getting engaged. I was very surprised by that and of course very happy. The reason why I was very surprised by that is because it is not something that occurs very often in my life. Or because I am just getting older and older (though I am only 24), that kind of event will occur more often that usual because all my friends and I are getting in a period where we can officially work, have a career, get married and have kids.
Actually, that wasn't the only factor that I was affected by this event. That we are getting adults. But I started questioning myself. What am I doing for god's sake. Sometimes you lose yourself in trying to make long terms plans for your life and for your career and you lose the reality and what is happening around you. You forget to be happy. You forget that you can actually love someone, meet someone or even have a conversation with someone. As an individual who always had issues on having intimate relationships with the opposite sex, it gave me a chance to question myself. And I am happy for that.
When I think about my past relationships, I can't stop thinking about the notion space and time. Thought I was always close to my girlfriends in case of in the same city or even sometimes in the same house, the idea of making progress in life, achieving something always destroyed my relationships. And I wasn't always the guilty one. The objectives and our passions in our lives made us so different that our relationship became a conflict for them and it was something that we had to abandon. It always led us to loneliness.
Now, I am scared of having a relationship. One reason for that is because I cannot really trust anybody. You say "Relationship? What for?" You know that it is going to end with a failure again. Does it worth it? I don't know.