The Unpopular Friend

I have a group of friends, but I feel like I'm the unpopular one in the group. No one in the group ever texts me or invites me places or tags me in funny stuff they see on social media. I noticed one of my friends was having a bad day and I asked him if something was wrong and he didn't want to tell me, but he told another girl in the group. I know they care about me and enjoy my company, but I believe actions speak louder than words. It just sucks because I feel like I'll never find that one or even those life-long friends. I'm almost 21 and I've never had that. It makes me feel very lonely.