we (might) have a problem??

So, I've been dating my girlfriend for about 2 weeks(?) now, and recently I learned that my best friend has confessed his feelings to her earlier today. Yes, he already knew about me and my girl and was actually the one to help me tell her how I felt. He found his own girl around the same time I found mine so we were both happy in our own separate relationships, but they recently broke up leading to now. I feel super worried and anxious, but I want to be mature and trust both of them. Even so, I know it's gonna nag at me for who knows how long. Is there something I should do about this? Am I in some sort of drama that i was not made aware of?