I joined my sorority through a graduate chapter.
A.) Yes, I applied for membership when I was an undergrad.
B.) I did the same things I had been doing, except with a lot more tears. I continued my service, and I continued striving for my dream.
C.) A sista was BITTER!!! I couldn't even congratulate my Kappa friends properly, I was so bitter. I apologized for that recently.

But nothing took away from my purpose and my drive. It's hard to not keep striving when your roommate is a member of that org! It was hard, but I continued to support them, even after they had graduated. Keep being seen. Try not to be bitter. It's hard, but
nothing worth having is easy to get.
As far as advice, it's like everyone has said. There is a reason that you might get rejected. Everything is under God's plan, so don't even worry about it. I KNOW it hurts. But that's life. Take it in stride, and keep striving. I know now why I couldn't have my letters when I wanted them. God had a plan for me, and for my LS's. So see, if I had pledged undergrad, I wouldn't have met my LS and I wouldn't have been able to help her when she needed me, and vice versa. So, while I was bitter then, I understand now. You can't see it while you're in it, though. So it's really hard to give advice, because when you are hurting, you're not trying to hear it. At all. But believe me, if it is meant for you, SF's, you will have it. God said so. So trust and believe. Keep striving.