Are these your friends, or are they just happen to be people you consistently sit around with? Maybe try engaging into conversations with them nonetheless. If you're still feeling uncomfortable, awkward or feel like they are not socially engaging you, then you can maybe not sit with them the next time around.
But then, this is going to be the same routine with every group you decide to meet and befriend, you have to start some at this situation. Unless you decide to meet people where everyone doesn't know each other and you form the group this way. But in reality, this is uncommon unless you decide to join some sort of club where everyone is new to each other.
Enjoy any good things, even the little and menial ones, as you will never know what impending distresses could descend upon you in a moment.