 Part of a group of three friends, however since a few weeks I have been in a tight spot. My other friends have gotten close enough to always sitting together and chatting; I feel like I'm being unintentionally or maybe intentionally left out (though they've denied it, it is pretty obvious my presence is not wanted). One of them is a very funny person and the other seems to enjoy his company far more than mine. ( I tend to get quite nerdy and uninteresting in conversations). Initially I thought I was just being insecure but I can't seem to get the idea that I'm just an invasive friend who is a hindrance to their friendship out of my head. I've cried multiple times about this and this has been eating my head up for the past few days.  
**Should I just silently walk away and let them have a good time?** I feel this would have a better conclusion than expressing my concern to them which would draw out forced conversations and make stuff even more awkward between us.