<human>: Can you condense the text into a few key points?

I (23M) have a friend from work (~29F) who I have known for about 2 years. She announced one year ago that she was engaged and would be getting married this summer, but did not give a definite date. 

Fastrack to April of this year. My friend and I are talking alone and she mentions that she'd like me to come to the wedding. I accept. She gives me the date (25 August 2012) and asks if I will be bringing anyone. I tell her I won't be. She tells me that she'll let me know the time and location at a later date. She asks me not to mention it to anybody else from work, because many of them weren't invited. 

After having this conversation, I waited for her to give me a formal invite, or let me know the time and location. Many weeks passed, and she didn't mention it. I began to suspect that she had reconsidered her invitation, and I didn't confront her about it (it's kind of hard to say, "Hey, you know that wedding you're having? Can I still come?").  

Two weeks before the date of the wedding, I realised that I probably wasn't going to hear any more about it, so I booked a trip home to visit my family over the time of the wedding. Before I caught my flight, I sent her a text, wishing her a great wedding and a happy marriage. She didn't reply to the message. Posts on her facebook wall suggest that the wedding went very well.

I got back from visiting my family on Sunday. My friend called me in work yesterday, and I thought she might want to talk about the situation, but she kept the conversation brief and work related. Neither of us mentioned the wedding.

I'm pretty annoyed about the way this has gone down. I wouldn't have minded if she'd called me at some point and said, "Sorry, you can't come to my wedding any more." But she just acted as if she hadn't invited me. Am I right to expect an apology from my friend? Should I congratulate her on the wedding?
<bot>: Friend invited me to wedding, asked me to keep it secret. She didn't mention it again, and didn't provide me with the location/time details. I didn't go and I'm annoyed about the way it went down.